JP6238965B2 - Holographic wide-angle display - Google Patents

Description

  The present invention relates to a holographic wide-angle display.

(Related application)
This application claims the benefit of US Provisional Patent Application No. 61 / 687,436, filed on April 25, 2012, and US Provisional Patent Application No. 61 / 689,907, filed on June 15, 2012. To do. Each of these is incorporated herein by reference in its entirety.

(Color drawing)
The file of this patent or application contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the Office upon request and necessary fee.

  There is a need for a compact see-through data display capable of displaying image content ranging from symbol and alphanumeric arrays to high resolution pixelated images. The display needs to be highly transparent, and the displayed image content must be clearly visible even when superimposed on a light background. The display needs to provide full color with a high quality color range for optimal data visibility and effectiveness. A desirable feature is that the display should be easy to wear, natural and casual, which can have a form factor similar to ski goggles or more preferably sunglasses. Eye relief and pupils need to be large enough to avoid image loss while the head is moving, even for harsh military and sports activities. The image generator needs to be compact, solid state and low power consumption.

  The above goals have not been achieved by current technology. Current wearable displays deliver see-through, moderate pupils, eye relief and viewing angles and high brightness, but at the same time at the cost of bulky form factor. In many cases, weight is distributed in front of the eye where it is undesirable for a wearable display. One common approach to providing see-through relies on reflective or diffractive visors that receive off-axis illumination. A microdisplay that provides a high resolution image generator in a small flat panel often does not always help to reduce the wearable display. This is because an extremely high magnification is generally required, and the optical apparatus must have a large diameter. Several ultra-low form factor designs are currently available that provide spectacle-like form factors, but usually require aggressive tradeoffs with viewing angle (FOV), eye relief and exit pupil. The

The long-term goal for HMD (head mounted display) research and development is to create the following features of near-to-eye and color HMDs. That is,
a) a high resolution digital image that exceeds the resolution of standard NVG (Night Vision Goggles) over the entire viewing angle and is focused at infinity;
b) HMD with monocular viewing angle (FOV) of 80 ° × 40 °, or HMD with binocular FOV of 120 ° × 40 °, with a superposition of 40 ° stereoscopic viewing angle at the center of the FOV,
c) unobstructed panoramic view of the outside world, high see-through (over 90%) display with sufficient eyebox and moderate eye relief, and d) good for both step-in visor and standard sand, wind and dust goggles Lightweight and flat design integrated into

  Although the image is displayed over a given viewing angle, the panoramic see-through performance is much larger and generally better than the host visor or goggles. This is an improvement over existing NVG where the surrounding environment is blocked outside the viewing angle of 40 °.

  One desirable head-mounted display is one that maintains (1) panoramic see-through with high transparency and (2) provides high resolution and wide-field images. Such a system also needs to be modest, i.e. compact, lightweight and comfortable. Comfort is to have sufficient exit pupil and eye motion box / exit pupil (> 15 mm), moderate eye relief (≧ 25 mm), ergonomic center of mass, infinity focus, and integrity with protective headgear. Derived from. Current and future traditional refractive optics cannot meet this set of requirements. Other important identifiers include full color performance, viewing angle, pixel resolution, see-through, brightness, dynamic gray scale and low power consumption. Even after years of highly competitive development, HWD (head mounted display) based on refractive optics limits the viewing angle and is not compact, lightweight or comfortable.

  Head mounted displays based on waveguide technology substrate waveguide displays have demonstrated performance to meet many of these basic requirements. Of particular relevance is the patent (Patent Document 1) granted in 1999 to Kaiser Optical Systems (KOSI), a subsidiary of Rockwell Collins. This is how you can use a diffractive element at the input to couple light into the waveguide, and a second diffractive element at the output to decouple light from the waveguide. Teach. According to Patent Document 1, light incident on a waveguide needs to be collimated to maintain image content when propagating along the waveguide. That is, the light needs to be collimated before entering the waveguide. This can be accomplished by a number of suitable techniques. According to this design approach, the light exiting the waveguide is naturally collimated, which is a necessary condition to make the image appear in focus at infinity. Light propagates along the waveguide only over a limited range of interior angles. Light propagating parallel to the surface (by definition) travels along the waveguide without splashing. The light that does not propagate parallel to the surface travels along the waveguide while bouncing back and forth between the surfaces when the incident angle with respect to the normal of the surface is larger than a predetermined critical angle. For BK-7 glass, this critical angle is about 42 °. This can be reduced slightly by using a reflective coating (but this can reduce the see-through performance of the substrate) or by using a high index material. Nevertheless, the range of interior angles through which light propagates along the waveguide does not change significantly. Therefore, for glass, the maximum range of interior angles is 50 ° or less. This is interpreted as the range of angles exiting the waveguide (ie, the angle in the air) is less than 40 °. It is generally smaller when other design factors are taken into account.

  At present, SGO (Substrate Guided Optics) technology is not widely accepted. This is due to the fact that waveguide optics can be used to widen the exit pupil but cannot be used to widen the viewing angle or improve digital resolution. That is, the basic physics constraining the range of interior angles that can undergo total internal reflection (TIR) in the waveguide limits the view angle achievable for waveguide optics to a maximum of 40 °, and Limiting the achievable digital resolution to the resolution of the associated image.

US Pat. No. 5,856,842

  In view of the above, the inventor has recognized and evaluated the true value of displays that combine substrate waveguide optics (SGO) and switchable Bragg gratings (SBG) and in particular transparent displays.

  Accordingly, in one aspect of some embodiments, provided is an apparatus for displaying an image, an input image node configured to provide at least first and second image modulated light, and first and first And a holographic waveguide device configured to propagate at least one of the two image modulated lights in at least a first direction. The holographic waveguide device includes at least first and second scattered multi-grating elements disposed in at least one layer. The first and second grating elements have first and second formulations, respectively. The first and second image modulated lights are modulated by image information of the first viewing angle (FOV) and the second FOV, respectively. The first multiple grating element is configured to deflect the first image modulated light emitted from the at least one layer into a first multiple output beam that forms a first FOV tile. The second multiple grating element is configured to deflect the second image modulated light exiting the layer into a second multiple output beam that forms a second FOV tile.

  In another aspect of some embodiments, provided is a method for displaying an image, comprising: (i) one input image node, and M and N as integers (M × N) scattered multiple grating elements Providing one apparatus including one holographic waveguide device including: (ii) corresponding to viewing angle (FOV) tiles (I, J) for integers 1 ≦ I ≦ N and 1 ≦ J ≦ M Generating an image-modulated light (I, J) input image node, (iii) switching a plurality of grating elements of the prescription matched FOV tile (I, J) to these diffraction states, and (iv) prescription matching Illuminating a plurality of grating elements of the FOV tile (I, J) with image-modulated light (I, J); (v) diffracting the image-modulated light I, J into FOV tiles I, J; In a way that includes That.

  A more complete understanding of the present invention can be obtained by considering the following detailed description in conjunction with the accompanying drawings in which like reference numerals indicate like parts, and in which: For the purpose of clarity, details related to technical matters known in the technical field related to the present invention are not described in detail.

  It is to be noted that all combinations of the above concepts with additional concepts described in detail below (which concepts are not inconsistent with one another) are considered as part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are considered to be part of the inventive subject matter disclosed herein. It should be noted that terms that are explicitly used herein and appear in any disclosure incorporated by reference are given the meaning most consistent with the specific concepts disclosed herein.

  Those skilled in the art will appreciate that the drawings are primarily for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale. In some instances, various aspects of the inventive subject matter disclosed herein may be exaggerated or enlarged in the drawings to facilitate understanding of different features. In the drawings, like reference characters generally refer to the same features (eg, functionally similar and / or structurally similar elements).

FIG. 1 is a schematic diagram of a color waveguide display architecture using stacked gratings. Each grating prescription corresponds to the waveguide light being diffracted into a unique viewing angle tile. FIG. 2 is a schematic cross-sectional view of a waveguide display in one embodiment using a laminated grating showing the FOV provided by each grating. FIG. 3A is a schematic cross-sectional view of a tessellated waveguide display in one embodiment showing details of the tessellation pattern. FIG. 3B is a schematic cross-sectional view of a tessellated waveguide display in one embodiment showing details of a tessellation pattern in which grating elements are evenly distributed. FIG. 3C is a schematic cross-sectional view of a tessellated waveguide display in one embodiment showing details of a tessellation pattern in which grating elements are randomly scattered. FIG. 4 is a schematic front view of the functional elements of a tessellated waveguide display in one embodiment. FIG. 5 is a schematic front view of a tessellated waveguide display in one operational state in one embodiment. FIG. 6 is a schematic front view of a tessellated waveguide display showing details of an input image node in one embodiment. FIG. 7 illustrates the operation of the input image node in one embodiment. FIG. 8A is a tessellation pattern that includes rectangular elements of different sizes and aspect ratios in one embodiment. FIG. 8B is a tessellation pattern including a Penrose tile in one embodiment. FIG. 8C is a tessellation pattern including a hexagon in one embodiment. FIG. 8D is a tessellation pattern including a square in one embodiment. FIG. 9A is a tessellation pattern including diamond elements in one embodiment. FIG. 9B is a tessellation pattern including an isosceles triangle in one embodiment. FIG. 10A is a tessellation pattern that includes horizontally deflected aspect ratio hexagons in one embodiment. FIG. 10B is a tessellation pattern that includes horizontally deflected aspect ratio rectangles in one embodiment. FIG. 10C is a tessellation pattern that includes horizontally deflected aspect ratio diamond elements in one embodiment. FIG. 10D is a tessellation pattern that includes horizontally deflected aspect ratio triangles in one embodiment. FIG. 11 is a schematic cross-sectional view of a tessellated waveguide that includes two grating layers in one embodiment. FIG. 12A illustrates an example of a tessellation pattern that includes four different grating element types in one embodiment with the eye pupils superimposed. FIG. 12B illustrates an example of a tessellation pattern that includes one grating element type in one embodiment with the eye pupil superimposed. FIG. 12C illustrates an example of a tessellation pattern that includes two different grating element types in one embodiment with the eye pupils superimposed. FIG. 12D shows an example of a tessellation pattern that includes three different grating element types in one embodiment, with the eye pupil superimposed. FIG. 13 shows an example of a tessellation pattern for one particular grating element type in one embodiment with the eye pupils superimposed. 14 is a chart showing MTF (Modulation Transfer Function) versus angular frequency for the tessellation pattern of FIG. 13 in one embodiment. FIG. 15 shows an example of a tessellation pattern using rectangular elements having horizontally deflected aspect ratios and including five different types of elements in one embodiment. FIG. 16A illustrates the projection of the first type of tessellation element corresponding to the first viewing angle in one embodiment onto the exit pupil with the eye pupil superimposed. FIG. 16B illustrates the projection of the second type of tessellation element corresponding to the second viewing angle in one embodiment onto the exit pupil, with the eye pupil superimposed. FIG. 16C illustrates the projection of the third type tessellation element corresponding to the third viewing angle in one embodiment onto the exit pupil, with the eye pupil superimposed. FIG. 16D shows a viewing angle tile corresponding to the tessellation element of FIG. 16A in one embodiment. FIG. 16E shows a viewing angle tile corresponding to the tessellation element of FIG. 16B. FIG. 16F illustrates a viewing angle tile corresponding to the tessellation element of FIG. 16C in one embodiment. FIG. 17 shows the distribution of tessellation element types within the regions labeled 1 through 7 that are used to provide the viewing angle tiling pattern illustrated in FIG. 18 in one embodiment. FIG. 18 shows a viewing angle tiling pattern that includes four horizontal tiles and three vertical tiles. FIG. 19A illustrates a tessellation pattern that includes one type of elements from regions 1 and 7 in one layer of the two-layer waveguide of the example illustrated in FIGS. 17-18 in one example. FIG. 19B shows superimposed tessellation patterns from both layers of the waveguide of FIG. 19A in one embodiment. FIG. 20A illustrates a tessellation pattern that includes one type of elements from regions 2 and 6 in one layer of the two-layer waveguide of the example illustrated in FIGS. 17-18 in one example. FIG. 20B shows a superimposed tessellation pattern from both layers of the waveguide of FIG. 20A in one embodiment. FIG. 21A shows a tessellation pattern including one type of elements from regions 3 and 5 in one layer of the two-layer waveguide in the embodiment of the invention illustrated in FIGS. 17-18 in one embodiment. . FIG. 21B shows superimposed tessellation patterns from both layers of the waveguide of FIG. 21A in one embodiment. FIG. 22A shows a tessellation pattern including one type of element from region 4 in one layer of the two-layer waveguide in the embodiment of the invention illustrated in FIGS. FIG. 22B shows a superimposed tessellation pattern from both layers of the waveguide of FIG. 22A in one embodiment. FIG. 23 illustrates a composite tessellation pattern resulting from the overlay of the tiled patterns of FIGS. 19A-22B in one embodiment. FIG. 24 shows an example of a tessellation pattern in a two-layer waveguide for only one type of grating element in one embodiment. FIG. 25 shows a composite tessellation pattern in the first layer of a two-layer waveguide in one embodiment. FIG. 26 shows a composite tessellation pattern in the second layer of a two-layer waveguide in one embodiment. FIG. 27A is a schematic cross-sectional view showing an image output portion of an input image node in one embodiment. FIG. 27B is a schematic cross-sectional view showing an image input portion of an input image node in one embodiment. FIG. 28A is a cross-sectional view illustrating an input image node and coupling of the input image node to a DigiLens® waveguide via a vertical beam expander in one embodiment. FIG. 28B shows the ray trace of the embodiment of FIG. 28A in one embodiment. FIG. 29 is a plan view of a DigiLens waveguide and a vertical beam expander in one embodiment. FIG. 30A shows a waveguide 252 in one embodiment with input rays directed into the TIR path by a coupled grating. FIG. 30B shows a waveguide in one embodiment with input coupling optics. The input coupling optical device includes a first and second gratings disposed adjacent to each other, a half-wave film sandwiched between the waveguide and the first grating, and a sandwich between the waveguide and the second grating. Polarizing beam splitter (PBS) film. FIG. 31 is a schematic cross-sectional view of a portion of a waveguide used in the present invention in one embodiment. Light is extracted from the waveguide in the opposite direction. FIG. 32 is a schematic cross-sectional view of a portion of a waveguide used in the present invention that incorporates a beam splitter layer to improve illumination uniformity in one embodiment. FIG. 33 illustrates a method for reducing the number of wiring tracks in an electrode layer using double-sided addressing in one embodiment. FIG. 34 illustrates one scheme for alternating electrode wiring tracks in a tessellated waveguide in one embodiment. FIG. 35 illustrates another scheme for alternating electrode wiring tracks in tessellated waveguides in one embodiment. FIG. 36 illustrates a further scheme for interleaving electrode wiring tracks in a tessellated waveguide in one embodiment. FIG. 37A shows a schematic plan view of a curved visor implementation of the present invention in one embodiment. FIG. 37B shows a schematic side view of the curved visor implementation of the present invention in one embodiment. FIG. 38 shows a cross section of the curved visor implementation of the present invention in one embodiment. A DigiLens includes a stack of optically isolated waveguides. FIG. 39 shows a cross section of the curved visor implementation of the present invention in one embodiment. The DigiLens includes a stack of grating layers that form a single waveguide structure. FIG. 40A shows a cross-sectional view of the curved visor implementation of the present invention in one embodiment. The DigiLens includes a facet element. FIG. 40B shows the optical interface between the two facet elements of FIG. 40A in one embodiment. FIG. 40C illustrates in detail the optical interface between the two facet elements of FIG. 40A in one embodiment. FIG. 41 shows a cross section of the curved visor implementation of the present invention in one embodiment. The DigiLens includes a facet element embedded in the curved optical waveguide. FIG. 42A is a chart showing the variation in diffraction efficiency for each angle for a micro-tessellated pattern of one embodiment of the present invention in one embodiment. FIG. 42B shows a micro tessellation distribution corresponding to the chart of FIG. 42A in one embodiment. FIG. 43A is a chart showing an MTF (Modulation Transfer Function) plot for a regular micro tessellation pattern with an aperture fill factor of 50% in one example. FIG. 43B is a schematic illustration showing the effect of 50% aperture fill generated by the micro tessellation pattern of FIG. 43A in one embodiment. FIG. 44A is a chart showing an MTF plot for a regular micro tessellation pattern with an aperture fill factor of 25% in one example. FIG. 44B is a schematic illustration showing the effect of 25% aperture fill produced by the micro tessellation pattern of FIG. 43A in one embodiment. FIG. 45A is a chart showing an MTF plot for a regular micro tessellation pattern with 50% aperture fill in one example. FIG. 45B is a footprint diagram for the case of FIG. 45A in one embodiment. FIG. 46A is a footprint diagram showing the effect of 75% aperture fill for 50 micron micro tessellations in one embodiment. FIG. 46B is a chart showing an MTF plot illustrating the effect of 75% aperture fill for 50 micron micro tessellations in one embodiment. FIG. 47A is a footprint diagram showing the effect of 50% aperture fill for 50 micron micro tessellations in one embodiment. FIG. 47B is a chart showing an MTF plot illustrating the effect of 50% aperture fill for 50 micron micro tessellations in one embodiment. FIG. 48A is a footprint diagram illustrating the effect of 25% aperture fill for 50 micron micro tessellations in one embodiment. FIG. 48B is a chart showing an MTF plot illustrating the effect of 25% aperture fill for 50 micron micro tessellations in one embodiment. FIG. 49A is a footprint diagram showing the effect of 75% aperture fill for 125 micron micro tessellations in one embodiment. FIG. 49B is a chart showing an MTF plot illustrating the effect of 75% aperture fill for 125 micron micro tessellations in one embodiment. FIG. 50A is a footprint diagram showing the effect of 50% aperture fill for 125 micron micro tessellations in one embodiment. FIG. 50B is a chart showing an MTF plot illustrating the effect of 50% aperture fill for 125 micron micro tessellations in one embodiment. FIG. 51A is a footprint diagram showing the effect of 25% aperture fill for 125 micron micro tessellations in one embodiment. FIG. 51B is a chart showing an MTF plot illustrating the effect of 25% aperture fill for 125 micron micro tessellations in one embodiment. FIG. 52A is a footprint diagram showing the effect of 75% aperture fill for 250 micron micro tessellations in one embodiment. FIG. 52B is a chart showing an MTF plot illustrating the effect of 75% aperture fill for 250 micron micro tessellations in one embodiment. FIG. 53A is a footprint diagram showing the effect of 50% aperture fill for 250 micron micro tessellations in one embodiment. FIG. 53B is a chart showing an MTF plot illustrating the effect of 50% aperture fill for 250 micron micro tessellations in one embodiment. FIG. 54A is a footprint diagram illustrating the effect of 25% aperture fill for 250 micron micro tessellations in one embodiment. FIG. 54B is a chart showing an MTF plot illustrating the effect of 25% aperture fill for 250 micron micro tessellations in one embodiment. FIG. 55A is a footprint diagram showing the effect of 1 mm tessellation at 50% aperture fill for 125 micron micro tessellations for an eye pupil diameter of 3 mm in one example. FIG. 55B is a chart showing an MTF plot illustrating the effect of 1 mm tessellation at 50% aperture fill for 125 micron micro tessellation for an eye pupil diameter of 3 mm in one example. FIG. 56A is a footprint diagram showing the effect of 1.5 mm tessellation at 50% aperture fill for 125 micron micro tessellation for an eye pupil diameter of 3 mm in one example. FIG. 56B is a chart showing an MTF plot illustrating the effect of 1.5 mm tessellation at 50% aperture fill for 125 micron micro tessellations for an eye pupil diameter of 3 mm in one example. . FIG. 57A is a footprint diagram showing the effect of 3 mm tessellation at 50% aperture fill for 125 micron micro tessellation for an eye pupil diameter of 3 mm in one example. FIG. 57B is a chart showing an MTF plot illustrating the effect of 3 mm tessellation at 50% aperture fill for 125 micron micro tessellations for an eye pupil diameter of 3 mm in one example. FIG. 58A is a chart illustrating the MTF of a user-defined aperture in one embodiment. FIG. 58B is a chart showing the MTF of the bitmap aperture function in one embodiment. FIG. 59A is a bitmap aperture function of one embodiment of the present invention in one embodiment. FIG. 59B is a chart showing diffraction efficiency versus angle for the example of FIG. 59A in one example. FIG. 60 is an MTF plot showing the effect of 1.0 mm tessellation using 125 μm micro tessellation randomly positioned with variable transmittance and 3 mm eye pupil in one example. FIG. 61 is a bitmap aperture function in one embodiment. FIG. 62 is an MTF plot showing the effect of 1.5 mm tessellation using 125 μm micro tessellation randomly positioned with variable transmission and 3 mm eye pupil in one example. FIG. 63 is a first illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 64 is a second illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 65 is a third illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 66 is a fourth illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 67 is a fifth illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 68 is a sixth illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 69 is a seventh illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 70 is an eighth illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 71 is a ninth illuminance uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 72 is a tenth illumination uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 73 is an eleventh illumination uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 74 is a twelfth illumination uniformity analysis of the first mounting tessellation pattern in one embodiment. FIG. 75 is a thirteenth illumination uniformity analysis of the first mounting tessellation pattern of the example according to the example.

  A detailed description of various concepts and embodiments associated with the display of the present invention is provided below. It should be noted that the various concepts introduced above and described in detail below can be implemented in any number of ways, but the described concepts are not limited to any particular implementation. Specific implementations and applications are given, primarily for illustrative purposes.

Various examples

  In one embodiment, provided is an apparatus for displaying an image, wherein an input image node configured to provide at least first and second image modulated light, and at least one of first and second image modulated light. And a holographic waveguide device configured to propagate at least in a first direction. The holographic waveguide device includes at least first and second interspersed multiple grating elements disposed in at least one layer, the first and second grating elements having first and second formulations, respectively. The first and second image modulated lights are modulated by the first viewing angle (FOV) and the second FOV image information, respectively. The first multiple grating element is configured to deflect the first image modulated light from the at least one layer to a first multiple output beam to form a first FOV tile, the second multiple grating element Is configured to deflect second image modulated light from the layer to a second multiple output beam to form a second FOV tile.

  In another embodiment, an apparatus for displaying an image includes an input image node configured to provide at least first and second image modulated light, and first and second image modulated light. And a holographic waveguide device configured to propagate at least one of at least in a first direction. The holographic waveguide device is at least first and second scattered multi-grating elements disposed in at least one layer. The first and second grating elements have first and second prescriptions, respectively. The first and second image modulated lights are modulated by the first viewing angle (FOV) and the second FOV image information, respectively. The first multiple grating element is configured to deflect the first image modulated light from the at least one layer to a first multiple output beam to form a first FOV tile, the second multiple grating element Is configured to deflect second image modulated light from the layer to a second multiple output beam to form a second FOV tile. The first and second multiple grating elements include SBGs that are in passive mode or switched mode.

  In another embodiment, an apparatus for displaying an image is provided, the input image node configured to provide at least first and second image modulated light, a beam expander, and first and first images. And a holographic waveguide device configured to propagate at least one of the two image modulated lights in at least a first direction. The holographic waveguide device includes at least first and second scattered multi-grating elements disposed in at least one layer. The first and second grating elements have first and second formulations, respectively. The first and second image modulated lights are modulated by image information of the first viewing angle (FOV) and the second FOV, respectively. The first multiple grating element is configured to deflect the first image modulated light from the at least one layer to a first multiple output beam to form a first FOV tile, the second multiple grating element Is configured to deflect second image modulated light from the layer to a second multiple output beam to form a second FOV tile.

  In another embodiment, an apparatus for displaying an image includes an input image node configured to provide at least first and second image modulated light, and first and second image modulated light. And a holographic waveguide device configured to propagate at least one of the at least one in a first direction. The holographic waveguide device includes at least first and second scattered multi-grating elements disposed in at least one layer. The first and second grating elements have first and second formulations, respectively. The first and second image modulated lights are modulated by image information of the first viewing angle (FOV) and the second FOV, respectively. The first multiple grating element is configured to deflect the first image modulated light from the at least one layer to a first multiple output beam to form a first FOV tile, the second multiple grating element Is configured to deflect second image modulated light from the layer to a second multiple output beam to form a second FOV tile. At least one of the first and second multiple grating elements is tessellated in a predetermined pattern.

  In one embodiment, at least one of the first and second multiple grating elements includes an SBG (switchable Bragg grating) that is in a switching mode or a passive mode.

  In one embodiment, at least one of the first and second multiple grating elements is electrically switchable.

  In one embodiment, at least one of the first and second multiple grating elements has a non-diffractive state and a diffractive state having a diffraction efficiency that is between a predetermined minimum level and a maximum level.

  In one embodiment, all elements in the first or second multiple grating element are configured to be switched.

  In one embodiment, at least one of the first and second multiple grating elements has a diffractive state and is in the diffractive state. The first grating element is configured to deflect the first image modulated light from the at least one layer into a first multiple output beam to form a first FOV tile. The second grating element is configured to deflect second image modulated light from the layer to a second multiple output beam to form a second FOV tile.

  In one embodiment, the at least one layer is sandwiched between transparent substrates to which patterned electrodes are applied.

  In one embodiment, the at least one layer is sandwiched between transparent substrates to which the patterned electrodes are applied, and at least one of the patterned electrodes is a first multiple first grating element. And a second multiple electrode element overlapping the second multiple second grating element.

  In one embodiment, at least one of the first and second multiple grating elements has a spatially dependent diffraction efficiency.

  In one embodiment, at least one of the first and second multiple grating elements has a diffraction efficiency that increases with distance along the length of the waveguide.

  In one embodiment, in the at least one layer, the grating elements are in the first band, with a different prescription of integer N2 if N1> N2, N3 different prescriptions if N2> N3, and N3 For> N4, bands containing elements of different prescriptions of integer N4 have different prescriptions of integer N1 scattered in continuous contact with the left and right. In one embodiment, at least one of the first and second multi-grating elements has a band that includes nine different prescriptions, six different prescriptions, and one prescription element within the first band. It has 12 different prescriptions scattered in contact with the left and right in succession.

  In one embodiment, each FOV tile is configured to provide an image at infinity.

  In one embodiment, each FOV tile is configured to provide an image at the far point of the human eye.

  In one embodiment, the holographic waveguide device includes at least one of a beam splitter thin layer for polarization recovery, a quarter wave plate, and a grating device.

  In one embodiment, image modulated light from at least one grating element of a given prescription is present in the exit pupil region bounded by the instantaneous aperture of the human eye pupil. In one embodiment, there is image modulated light from at least three grating elements of a given prescription.

  In one embodiment, the FOV tiles abut in the FOV space to form a rectangular FOV.

  In one embodiment, FOV tiles abut in the FOV space to provide a continuous viewing angle.

  In one embodiment, at least two of the FOV tiles overlap.

  In one embodiment, the FOV tiles abut to give an FOV approximately 40 degrees horizontal x 30 degrees vertical.

  In one embodiment, the FOV tiles abut to give an FOV approximately 60 degrees horizontal x 30 degrees vertical.

  In one embodiment, the FOV tiles abut to give an FOV approximately 80 degrees horizontal x 80 degrees vertical.

  In one embodiment, the input image node further includes a speckle remover.

  In one embodiment, at least one of the first and second multiple grating elements is recorded on a HPDLC (Holographic Polymer Dispersed Liquid Crystal).

  In one embodiment, at least one of the first and second multiple grating elements is a reverse mode SBG (switchable Bragg grating).

  In one embodiment, the holographic waveguide device is curved.

  In one embodiment, the first and second multiple grating elements have different thicknesses.

  In one embodiment, the holographic waveguide device includes facet sections that abut edges.

  In one embodiment, a holographic waveguide device includes a facet section that abuts edges and is embedded in a plastic continuous curved volume.

  In one embodiment, the holographic waveguide device includes plastic.

  In one embodiment, the holographic waveguide device is configured to provide an extension of the exit pupil in a first direction and the beam expander is configured to provide an extension of the exit pupil in a second direction.

  In one embodiment, the holographic waveguide device is configured to provide expansion in the first direction of the exit pupil and the beam expander extends in a second direction orthogonal to the first direction of the exit pupil. Configured to give

  In one embodiment, the beam expander further includes an input port for image modulated light from the input image node, an output port, and at least one waveguide layer configured to propagate the light in the second direction. including. The at least one waveguide layer includes at least one thin grating layer configured to extract modulated light from the substrate along the second direction and direct it through the output port in the first direction.

  In one embodiment, the beam expander further includes at least one waveguide layer including at least two grating thin layers disposed adjacent to each other.

  In one embodiment, the beam expander further includes at least one waveguide layer that includes at least two overlapping grating laminae.

  In one embodiment, the beam expander includes at least one of a thin beam splitter layer for polarization recovery, a quarter wave plate, and a grating device.

  In one embodiment, the first and second image modulated lights are presented continuously.

  In one embodiment, at least one of the first and second modulated image light undergoes total internal reflection (TIR) within the waveguide device.

  In one embodiment, the input image node includes at least one of a microdisplay, a light source configured to illuminate the microdisplay, a processor that writes image data to the microdisplay, and a collimation lens, a relay lens, a beam splitter, and a magnification lens. Including one.

  In one embodiment, the first and second multiple grating elements are tessellated into a predetermined pattern.

  In one embodiment, the predetermined pattern is at least one of a periodic pattern, an aperiodic pattern, a self-similar pattern, a non-self-similar tiling pattern, and a random distribution pattern. In one embodiment, the aperiodic pattern is a Penrose tiled pattern. In another embodiment, the self-similar pattern is a Penrose tiling pattern.

  In one embodiment, all elements in the first or second multi-grating element are configured to be switched to the diffractive state simultaneously.

  In one embodiment, at least one of the first and second multiple grating elements has at least one axis of symmetry.

  In one embodiment, at least one of the first and second multiple grating elements has a shape that includes at least one of a square, a triangle, and a diamond.

  In one embodiment, the plurality of elements of the first multiple grating element have a first geometry and the plurality of elements of the second multiple grating element have a second geometry.

  In one embodiment, at least one of the first and second grating elements has at least two different geometric shapes.

  In one embodiment, all grating elements in the at least one layer are optimized for one wavelength.

  In one embodiment, at least one of the first and second grating elements in the at least one layer is optimized for at least two wavelengths.

  In one embodiment, at least one of the first and second grating elements has a multiplexed recipe that is optimized for at least two different wavelengths.

  In one embodiment, at least one of the first and second grating elements has a multiplexed recipe that is optimized for at least two different diffraction efficiency angular bands.

  In one embodiment, at least one of the first and second image modulated light is collimated.

  In one embodiment, at least one of the first and second image modulated light is polarized.

  In one embodiment, the apparatus further includes an illumination source that includes a laser that provides at least one wavelength of light.

  In one embodiment, the holographic waveguide device is configured to provide a transparent display.

  In some embodiments, a device is provided that includes the apparatus described herein. The device is part of a reflective display. The device is part of a stereoscopic display in which the first and second image modulated light provides a left eye and right eye viewpoint view. The device is part of a real image forming display. The device is a part of at least one of HMD, HUD, and HDD. The device is part of a contact lens.

  In one embodiment, the input image node includes at least one of a microdisplay, a light source configured to illuminate the microdisplay, a processor that writes image data to the microdisplay, and a collimation lens, a relay lens, a beam splitter, and a magnification lens. Including one.

  In another embodiment, provided is a method for displaying an image, comprising: (i) one input image node and one hologram including scattered multiple grating elements, where M and N are integers (M × N). And (ii) image modulated light corresponding to the viewing angle (FOV) tile (I, J) for integers 1 ≦ I ≦ N and 1 ≦ J ≦ M. I, J) generating an input image node, (iii) switching a plurality of grating elements of the prescription matched FOV tile (I, J) to these diffraction states, and (iv) prescription matching FOV tile (I, J) J) illuminating a plurality of grating elements with image modulated light (I, J), and (v) diffracting the image modulated light I, J into FOV tiles I, J. .

  In one embodiment, the method further includes repeating (ii)-(v) until a complete FOV tile is achieved.

  In one embodiment, the method further includes sampling the input image into a plurality of angular intervals, each of the plurality of angular intervals having a single effective exit pupil that is a fraction of the size of the entire pupil. Including that.

  In one embodiment, the method further includes grating thickness, refractive index modulation, k vector, surface grating period, and hologram-substrate refractive index difference of at least one of the first and second optical substrates. Improving the display of the image by modifying at least one of the following:

  It should be noted that all combinations of the above concepts and additional concepts described in detail below (as long as such concepts do not contradict each other) are intended as part of the inventive subject matter described herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as part of the inventive subject matter described herein. It should be noted that terms explicitly used herein and appearing in any disclosure incorporated by reference should also be given the meaning most consistent with the specific concepts described herein.

  At least some examples given herein are the task of tiling a large FOV using multiple different grating formulations in a waveguide HMD of the type disclosed in US Pat. No. 8,233,204. Overcome. In one embodiment, the grating angular bandwidth constraint limits the size of the FOV tile to about 10 ° × 10 °, resulting in an unmanageably large grating stack-up as the number of vertical and horizontal FOV tiles increases. Is brought about. If one tries to achieve full color, the number of layers increases by three orders of magnitude.

  One important feature of the embodiments described herein is that instead of laminating different formulations of gratings, they are chopped into small elements. The small elements are then interspersed into a tessellation pattern in one or more overlapping layers.

  In one embodiment, the tessellated display includes an input image node (IIN), a first beam expander waveguide (usually in the vertical direction), and a second beam expander guide that also functions as an eyepiece. Waveguide (usually in the horizontal direction). In one embodiment, the eyepiece combines a tessellation function and a beam expansion function. Each waveguide includes input and output Bragg gratings. Each waveguide includes more than one grating layer. In the color embodiment, a separate monochrome waveguide is used for each primary color. Another option for providing color is to record multiplexed gratings in one waveguide on which holograms with different color recipes are superimposed. Multiplexing is also used to combine gratings with different angular bands.

  Many different tessellation schemes are possible. These include periodic (ie, invariant under lateral displacement), aperiodic, self-similar and random schemes. The pattern is designed to give details near the central FOV. The embodiments provided herein include passive or switchable tessellation solutions and include hybrid solutions that combine passive and switchable elements.

  In one embodiment, the rays diffracted from each tessellation element form a footprint at the exit pupil. Typically, at least two such footprints are required within the instantaneous eye pupil area. The exact number depends on factors such as tessellation size and shape. In one embodiment, tessellation presents significant design and manufacturing challenges. Small (a few millimeters) grating elements result in loss of resolution and illumination ripple. Both of these have proven difficult to correct. Holographic recording and electrode patterning of tessellated holographic arrays is difficult with current processes. These challenges can be overcome by using passive grating elements. In one embodiment, thinning the grating increases the bandwidth in the tangential plane while achieving broadband in the orthogonal and sagittal plane. Tessellation will provide a great path to FOV if the above design and manufacturing issues can be solved. Color 80 ° × 80 ° FOV is a reasonable goal.

  One embodiment uses separate vertical and horizontal beam expansion waveguides to provide an enlarged exit pupil (or eyebox). In one embodiment, collimated image light from the IIN is provided to a first beam-expanding waveguide in which the FOV is defined by a microdisplay and collimating optics. One embodiment allows the input or “couple” optics to be configured in many different ways. Such aspects range from classical optical lens / mirror designs to compact designs based entirely on diffractive (holographic) optics. One embodiment is implemented using a completely passive grating (although the use of a switchable grating is preferred for large FOVs). It does not work with conventional passive gratings. One advantage of using a passive SBG is that the refractive index modulation of the grating can be tuned from very low to very high with a corresponding wide range of diffraction efficiencies. The high refractive index modulation of SBG is caused by the bands of alternating polymer-rich regions and LC (Liquid Crystal) -rich regions that form Bragg stripes. Alternatively, active gratings can also be used. The active grating can be tuned from a very low value to a very high value with a corresponding wide range of diffraction efficiencies.

  Vertical and horizontal beam expanders are based on lossy waveguides. That is, a waveguide that is designed to uniformly extract light from the waveguide along its length. This can be achieved by changing (and modulating) the thickness of the grating, as demonstrated in US patent application Ser. No. 13 / 844,456, filed March 15, 2013. In one embodiment, in its simplest case this involves making a wedged grating (by tilting the cell wall). As a result, the thickness of the hologram increases in the propagation direction. In general, the thickness of the grating varies from 1.0 to 1.2 microns to 2.8 to 3.0 microns. If the thickness is small, the minimum efficiency (and the maximum angle band) is achieved. Some embodiments have refined extraction in a general manner by using two wedge angles to change the thickness in the orthogonal direction or by applying curvature to one or both sides of the grating Allow control.

  In one embodiment, the beam expansion grating is very thin (much smaller than 3 microns). As a result, an extremely wide diffraction efficiency angle band can be obtained. By optimizing the thickness and refractive index modulation, all of the desired grating properties required for the display can be met. The characteristic is, for example, extremely high efficiency for coupling to the grating, a large dynamic range for the efficiency, and uniform extraction required for beam expansion.

  Image sampling can be used to improve image transfer efficiency and form factor. Coupling wide FOV image light into a waveguide typically results in some loss of image angle content that can be efficiently propagated to the waveguide due to the limited angular range. A portion of this light is decoupled from the waveguide. At least some embodiments described herein overcome this challenge by sampling the input image into multi-angle intervals. Each multi-angle interval has one effective exit pupil. The effective exit pupil is a ratio of the size of the entire pupil, and the thickness of the waveguide is correspondingly reduced.

  One feature of the embodiment given here is that it combines a fixed frequency surface grating at the input and output of each waveguide with the rotated k-vector. A surface grating is the intersection of a Bragg stripe and a substrate edge and describes (approximately) the basic ray optics of a waveguide. The k vector is a direction orthogonal to the Bragg grating, and the relationship between the diffraction efficiency of the grating and the angle characteristic will be described. By changing the k-vector direction to be along the waveguide propagation direction (k-vector rotation), first, providing efficient coupling of image light to the waveguide is secondly coupled once All the desired angular content can be reliably transmitted to the waveguide with high efficiency. The k-vector rotation is preferably increased by grating thickness control as described above.

  In general, the propagation of angular content into a waveguide can be optimized by finely tuning one or more of the following: That is, grating thickness, refractive index modulation, k vector rotation, surface grating period, and hologram / substrate refractive index difference. The tessellation pattern includes an infrared sensing element that implements a waveguide eye tracker.

SBG device

  One way to create a fairly large viewing angle is to analyze it into a set of small viewing angles (each of which meets the optical limitations of the waveguide), and these are recognized by the eye as a unified wide-angle display. It is to display continuously (time) as quickly as possible. One way to do this is by using holographic elements that can be switched on and off continuously very quickly. One desirable solution for providing such a switchable holographic element is a device known as a switchable Bragg grating (SBG).

  Optical design advantages of diffractive optical elements (DOEs) include inherent and efficient form factors and the ability to encode complex optical functions such as refractive power and diffusion into thin layers. Bragg gratings (commonly referred to as volume phase gratings or holograms) that provide high diffraction efficiency are widely used in devices such as head-up displays. An important class of Bragg grating devices is known as Switchable Bragg Grating (SBG). An SBG is a diffractive device formed by recording a volume phase grating or hologram in a polymer dispersed liquid crystal (PDLC) mixture. Typically, SBG devices are manufactured by first placing a thin film of a mixture of photopolymerizable monomer and liquid crystal material between parallel glass plates or substrates. One or both glass substrates support an electrode comprising, for example, a transparent indium tin oxide film, for applying an electric field between the PDLC layers. The volume phase grating is then recorded by illuminating the liquid material using two mutually coherent laser beams that interfere to form the desired grating structure. During the recording process, the monomers polymerize and the HPDLC mixture undergoes phase separation. Thereby, a region where fine liquid crystal droplets are densely formed is formed, and transparent polymer regions are scattered. Alternating regions of liquid crystal richness and liquid crystal depletion form the grating fringe plane. The resulting volume phase grating can exhibit very high diffraction efficiency. The diffraction efficiency can be controlled by the magnitude of the electric field applied between the PDLC layers. When an electric field is applied to the hologram via the transparent electrode, the natural orientation of the LC droplet is changed, thereby reducing the refractive index modulation of the fringes and lowering the hologram diffraction efficiency to a very low level. Note that the diffraction efficiency of the device can be adjusted, for example, by an applied voltage over a continuous range from an efficiency close to 100% with no voltage applied to substantially zero efficiency where a sufficiently high voltage is applied. .

  SBGs can be used to provide transmissive or reflective gratings for free space applications. The SBG is implemented as a waveguide device in which the HPDLC forms either a waveguide core or an evanescent coupling layer proximate to the waveguide. In one particular configuration, referred to herein as Substrate Guided Optics (SGO), the parallel glass plates used to form the HPDLC cell have a total internal reflection (TIR) optical waveguide structure. give. The light is decoupled from the SBG when it is diffracted by the switchable grating at an angle that exceeds the TIR condition. SGO is currently attracting attention in various display and sensor applications. Most of the early work on HPDLC was directed to reflection holograms, but transmissive devices are becoming much more versatile as optical system components.

  HPDLC used in SBG includes liquid crystal (LC), monomer, photoinitiator dye and copolymerization initiator. The mixture includes a surfactant. The patent and scientific literature includes many examples of material systems and processes that can be used to manufacture SBGs. Two basic patents are U.S. Pat. No. 5,942,157 by Sutherland and U.S. Pat. No. 5,751,452 by Tanaka et al. Both applications describe a combination of monomer and liquid crystal material suitable for manufacturing SBG devices.

  One well-known attribute of transmissive SBG is the tendency of LC molecules to align in a direction orthogonal to the grating fringe plane. The effect of LC molecular matching is that the transmissive SBG efficiently diffracts P-polarized light (ie, light having a polarization vector in the incident plane), but S-polarized light (ie, polarization vector orthogonal to the incident plane). The light has a diffraction efficiency of almost zero. A glass optical waveguide in air propagates light by total internal reflection when the internal incident angle exceeds about 42 degrees. Thus, typically, the transmissive SBG described herein diffracts input P-polarized light entering the waveguide from a TIR (total internal reflection) angle of about 42 to about 70 degrees, or TIR light at that angle. SBG design is used to diffract to the output light path.

  Normally, the SBG diffracts when no voltage is applied and is switched to an optical passive state when the voltage is applied at other times. However, the SBG can also be designed to operate in a reverse mode that diffracts when a voltage is applied and remains optically passive in all other cases. The method of manufacturing the reverse mode SBG is any suitable method as disclosed, for example, in international application GB2012 / 000680 by Popovich et al. The document also discloses how flexible plastic substrates are used to make SBGs to provide the advantages of improved durability, light weight and safety in near eye applications.

  The invention is further described below by way of example only with reference to the accompanying drawings. As will be apparent to those skilled in the art, the present invention may be practiced with some or all of the inventions described in the following description. For the purpose of illustrating the invention, well-known features of optical technology known to those skilled in the art of optical design and viewing displays have been omitted or simplified so as not to obscure the basic principles of the invention. Unless otherwise stated, the term “on-axis” in relation to the direction of a light beam or beam refers to propagation parallel to an axis perpendicular to the surface of the optical component described in connection with the present invention. In the following description, the terms light, ray, beam and direction are used interchangeably and in conjunction with each other to indicate the direction of propagation of light energy along a linear trajectory. Portions of the following description are presented using terms commonly used by those skilled in the art of optical design. It should also be noted that in the following description, repeated use of the phrase “in one embodiment” does not necessarily refer to the same embodiment.

  One important feature of the embodiment given here is that one way to create a fairly large viewing angle is to analyze the large viewing angle and set a small set of viewing angles (each adapted to the optical limitations of the waveguide). And that these are displayed continuously (time) at such a high speed that the eye recognizes them as a unified image.

  One way to do this is with a holographic element that can be switched on and off very quickly. US Provisional Patent Application No. 61 / 687,436, filed April 25, 2012, shows that multiple SBGs are the same to tile high resolution ultra wide viewing angles in a time-continuous manner. It can be laminated together in a waveguide and activated quickly and in succession. In addition, each sub-viewing angle has a full digital resolution of the associated image element, allowing the formation of images that are close to or even beyond the vision limit of the human eye.

  The tiling disclosed in this earlier application overcomes the twin defects of the standard wave guide architecture (ie limited viewing angle and limited pixel resolution) while maintaining vertical and horizontal over large viewing angles. There is a limit when it is necessary to tile in the direction. For a monochrome display with a small FOV and an extension in only one direction, tiling can be accomplished by simply stacking the grating planes. However, if the viewing angle is extended in both directions and color is added, the number of layers required by this approach quickly becomes impractical. For example, considering FIG. 1, a schematic diagram of a beam deflection system providing a display is shown. The display is based on the principle of using a stack 1 of electrically switchable grating SBGs to deflect the input light 100 from the image generator 2 into the FOV region or tile. In one embodiment, each SBG is essentially a planar grating beam polarizer. This deflects incident TIR light into output light that forms a unique FOV tile. SBG elements 10A-10D give four FOV tiles in the first row, elements 11A-11D give four FOV tiles in the second row, and elements 12A-12D give four FOV tiles in the third row . Advantageously, the image light is collimated and delivered to the SBG stack, for example by optical waveguide or substrate waveguide optics. The substrate used to contain the SBG provides an optical waveguide substrate. FIG. 2 shows how a horizontal viewing angle can be generated using four SBGs 10A-10D configured in four separate layers. One input SBG allows the input image light from the image generator to be directed into the TIR path. The input image generator includes a laser module, a microdisplay, and optics for collimation and beam expansion. The output SBG is staggered in the horizontal direction to provide image continuity in the FOV space. FIG. 2 shows limited rays in one plane for SBG group 3 corresponding to a row of FOV tiles 10A-10D. The maximum angular range θ1 for the limiting rays 101A-101D and the normals 102, 103 is shown. The rays define the exit pupil 104.

  In one embodiment, each sub-viewing angle is limited by the diffraction efficiency and angular band of the SBG. SBG grating devices have approximately an angular band ± 5 ° (influence of material properties, refractive index modulated beam geometry and thickness) in air. In one embodiment, in practice, large corners can be achieved by using thin SBGs. In one embodiment, the SBG has a thickness of about 4 μm or less, such as about 3.5 μm or less, 3 μm, 2.5 μm, 2 μm, 1.5 μm, 1 μm, less than 0.5 μm. Increased bandwidth due to thin SBGs results in low peak diffraction efficiency. In one embodiment, it is desirable to increase the refractive index modulation.

  In one example, the upper SBG 10A gives a viewing angle of −20 ° to −10 °, the next SBG 10B gives a viewing angle of −10 ° to 0 °, the next SBG 10C gives a viewing angle of 0 ° to 10 °, And the lower SBG 10D gives a viewing angle of 10 ° to 20 °. One gives 20 ° to the right. Each output FOV provides a FOV tile with a horizontal range of 10 degrees and a vertical range set by input collimation optics and waveguide limitations, typically 10 degrees. If SBG elements are displayed rapidly in succession (SBG has a switching speed as small as 35 microseconds, for example), the eye integrates separate light outputs, horizontal viewing angle 40 ° × vertical viewing angle 10 Degree is perceived. Each time a new output SBG is activated, the input image generator, indicated generally by 2, is updated with a new digital image. In one embodiment, the input image generator provides an image with a resolution of approximately 1000 pixels horizontally by 800 pixels vertically. Thus, the complete perceptual image has a 4000 × 800 pixel resolution. The tiles abut in the FOV space through the exit pupil defined by overlapping rays from the SBG layer. The HMD based on the above principle is the international application filed by the applicant on April 26, 2010 under the name “COMPACT HOLOGRAPHIC EDGE ILLUMINATED EYEGLASS DISPLAY” (and also referred to by the applicant's package number SBG073PCT). This is disclosed in GB2010 / 000835. This is incorporated herein by reference in its entirety.

  The stacking approach shown in FIG. 1 is suitable for relatively small FOVs. In one embodiment, a viewing angle of approximately 60 degrees in the horizontal direction and 10 degrees in the vertical direction can be achieved. As the viewing angle increases, the number of SBG layers required becomes impractical. That is, six layers are the current practical limit before display performance is compromised by scattering, absorption and other optical losses. If additional layers for blue and green, indicated schematically by 13, 14, are added, the number of tiles increases by a factor of three.

  One way to avoid using separate RGB SBGs is to use multiplexed SBGs. In this case, the illumination is given as R and B / G illumination from the opposite end of the optical waveguide, giving some concession to the color range. However, multiplexed gratings cause manufacturing complexity and crosstalk problems.

  One advantage of the embodiments described herein is that the need for a very large number of SBG layers is minimized. One embodiment provides for compressing the stack by interlacing SBGs, as shown in FIG. This is in contrast to simply laminating a grating as illustrated in FIGS. It can be seen with reference to the simple stacking scheme (inset) described above that an optical process that would normally require stacking of four holographic planes to produce a single color channel is used for interleaved gratings. It can be performed by a single layer. 1 to 3, the shading pattern of the hologram is only intended to distinguish four different types, and does not present the geometric shape of the grating.

  First, referring to the schematic side view of FIG. 3A, an apparatus for displaying an image including multiple groups of selectively switchable beam deflection elements is provided. In a preferred embodiment, the beam deflector is a plurality of SBGs having a first diffraction state and a second diffraction state. The first diffraction state shows high diffraction efficiency, and the second diffraction state shows low diffraction efficiency.

  In one embodiment, the SBG operates in a reverse mode that diffracts when a voltage is applied and remains optically passive in all other cases. SBGs are implemented as continuous thin SBG layers separated by a thin substrate layer (as thin as 100 microns). In one embodiment, the substrate comprises plastic. In one embodiment, the substrate comprises a plastic substrate having a transmissive conductive coating (instead of ITO).

  For convenience, four groups of SBG elements indicated by numbers 15 to 18 are illustrated. Each group includes four elements labeled with symbols AD. The repetition of the SBG element pattern is indicated by a dotted line. The number of groups of beam deflection elements or the number of elements per group is not limited. The element takes the form of a thin HPDLC grating thin layer 15 sandwiched between transparent substrates 14A, 14B. A transparent electrode is applied to the opposing surface of the substrate, and at least one of the electrodes has a pattern overlapping the SBG element.

  An input image generator, described in detail below, provides collimated image light, generally designated 100. Each group of beam deflection elements diffracts the image light into multiple rays that provide a set of FOV tiles. Multiple elements corresponding to a given tile have a unique grating prescription. The rays define the exit pupil according to geometric optical principles. Limited rays from groups 15 and 18 in the projection of the drawing are shown at 107,108. Each element has a diffraction efficiency angular band ± θ. As is apparent from a comparison between FIG. 3 and FIG. 2, the embodiment of FIG. 3 is equivalent to the SBG layer shown in FIG. 2 being interspersed within a single thin SBG layer. In one embodiment, the first multiple beam deflection element and the second multiple beam deflection element are evenly distributed as shown in FIG. 3B. In one embodiment, the first multiple beam deflection elements and the second multiple beam deflection elements are randomly scattered as shown in FIG. 3C.

  FIG. 3 shows the principle of HMD. A display based on the above principle includes two subsystems. That is, a color waveguide (also referred to herein as a DigiLens (registered trademark)) and a device configured to send an input image into the color waveguide (also referred to herein as an image feed node).

  The basic principle of the display in one embodiment is illustrated in detail using the front views of FIGS. In a color display, the DigiLens includes a stack of three individual RGB waveguides that each provide a red, green or blue color imaging channel. In one embodiment, each waveguide is further divided into two holographic layers (referred to as bilayers). In one embodiment, unless otherwise stated, the description assumes a double layer. Therefore, in FIG. 4, the digital lens 2 includes a double layer that further includes layers 21 and 22. The apparatus further includes an IIN (Input Image Node) 3, a digital lens drive electronics 4, and a coupler for putting light from the IIN into the digital lens.The communication link 103 between the IIN and the digital lens drive electronics. Each SBG layer includes multiple arrays of SBGs, which include multiple sets of subarrays, any given subarray whose members have one of a predetermined set of optical prescriptions. Each prescription corresponds to one unique FOV tile, the number of SBG prescriptions is equal to the number of FOV tiles, and in some embodiments, the prescription deflects the incident TIR input light from the IIN to FOV Defines the Bragg grating geometry required to produce the output light that defines the tiles. Two SBG element sub-arrays are illustrated, three elements of each sub-array being illustrated by symbols A to C. The drive electronics provide voltage outputs 103A to 103C.Connection 104A to SBG elements 300A to 300C The distribution of array elements depends on the FOV tile, eg, FOV tiles near the center area of the FOV require corresponding SBG elements to be distributed near the center of the DigiLens. 5 will be described in detail later, and Fig. 5 shows that the input collimated image light 200 from the IIN is coupled to a DigiLens to provide the collimated image light 201 at the input to the waveguide 2. SBG Typical collimated output beams from the waveguides for subarrays 200-202 are generally 202A- It is shown in 02C.

  In one embodiment, the SBG operates in a reverse mode that diffracts when a voltage is applied and remains optically passive in all other cases.

  The SBG is implemented as a continuous SBG thin layer separated by a thin substrate layer (as thin as 100 microns) as shown. This is a planar monolithic design that takes full advantage of the assets of narrowband laser illumination with monolithic holographic optics. The motivation for configuring the SBG as a monochrome layer is to use holographic optics and an SBG beam splitter to provide a flat, solid state and precision aligned display. This minimizes the need for bulky refractive optics. In one embodiment, the display resolution is limited only by the microdisplay resolution. The design can be scaled up to a large FOV by interlacing many tiles in each layer and / or adding new layers. Similarly, pupil, eye relief, and FOV aspect ratio can be tailored to suit the application.

  FIG. 6 shows in detail the IIN in one embodiment. The role of the IIN is to form a digital image, collimate it, and send it to the DigiLens. Two separate optical subsystems are used. One illuminates the microdisplay and one collimates the image. The IIN includes an image processor 3A, an input image generator 3B, and a vertical beam expander (VBE) 3C. The image processor provides image data to the input image generator via communication link 150. The image processor also controls the switching of SBG elements in the DigiLens by an electronic link with the DigiLens drive electronics. The input image generator described in detail in the following description includes a laser module and a microdisplay. Collimated image light 203 from the input generator is coupled to the beam expander 3C. The beam expander 3C itself is optically connected to the coupler 5. FIG. 7 illustrates the operation of the IIN in more detail focusing on the input image generator and VBE. Reference is made to the XYZ Cartesian axes given in the drawing. The front view corresponds to the YX plane, and the Y axis refers to the vertical direction perceived by the viewer of the display.

  The VBE (vertical beam expander) includes an SBG 60 sandwiched between substrates 61A and 61B. Image light from the image generator undergoes TIR (total internal reflection), indicated at 204, in a waveguide formed by the substrate. VBE is a lossy design. In other words, the diffraction efficiency of the grating is low at the end closest to the image generator and highest at the farthest end. One effect is that VBE couples light such as 204A, 204B towards its coupler 5 along its entire length, providing vertical beam expansion (in the Y direction) to match the height of the DigiLens waveguide. There is. Image light is coupled into VBE by a grating coupler 31A. Referring to the inset 62, there is further a holographic objective lens 31 and a holographic objective lens 32. Both are optically connected to the optical waveguide device 33. When image light from the microdisplay 207 enters the optical via via the holographic objective lens, it follows the TIR path 208, finally exits the optical waveguide, and is output into the VBE as output light 203 by the holographic objective lens 32. Directed. In one embodiment, the optical waveguide 33 includes a surface that is sloped at each end. Inset 63 shows the configuration of the laser module and the microdisplay. Illumination of the micro display 37 is performed using a diode laser 34, a waveguide and an SBG beam splitter. The SBG beam splitter is formed as a thin layer 36 sandwiched between transparent substrates 35A and 35B forming a waveguide. The tilted SBG grating is recorded on the portion of the thin layer 35A that overlaps the microdisplay. Collimated P-polarized light 210 from the laser module enters the waveguide via coupler 36. The coupler is a prism. In some embodiments, the coupler is a grating device. The combined light follows the TIR path 211 to the SBG beam splitter. Here, the P-polarized light is diffracted toward the micro display according to the characteristics of the SBG. The light is reflected to become S-polarized light, passes through the SBG beam splitter without substantial loss or deviation, and emerges from the waveguide as collimated image light 207.

  As will be apparent to those skilled in the art of optical design, many alternative optical designs and components can be used to provide an IIN according to the principles described herein.

  For example, a reflective microdisplay can be replaced with a transmissive device. Alternatively, emissive displays can be used. It is also clear that components such as anamorphic lenses and light shaping diffusing elements can be used to control image aspect ratio and illumination uniformity in a given application. The apparatus further includes a speckle remover. The IIN includes or is a diffractive light device. The process performed by IIN uses several refractive lenses, polarizing beam splitter cubes, and a precision housing to align and assemble various components, as used in the pre-existing technology. Not only are piece parts expensive, but also manual work becomes excessive. In addition, it is difficult to increase the durability of the entire assembly, and eventually it is heavy and bulky. Miniaturized components can reduce size and weight, but significantly increase component costs and assembly time.

  It is still clear that the IIN description has referred to just a single monochrome microdisplay. In a color display, the IIN optical component needs to be duplicated for each color. Since the optical design uses substrate waveguide optics and diffractive optical elements, the combination of red, green and blue channels in one embodiment can be accomplished in a very compact form factor. The form factor is limited only by the size of the microdisplay and laser module and the overall system design requirements.

  Interlacing of SBG elements in a DigiLens can be done in many different ways. For example, the interlaced grating in the embodiment of FIG. 1 can be configured in the manner of a Venetian blind (disclosed in provisional patent application 61 / 627,202 by the inventor). However, the MTF (Modulation Transfer Function) associated with such a geometry has multiple notches at spatial frequencies due to the periodic nature of the interleaving. In one embodiment, the introduction of multiple grating composite tessellation can correct this defect. “Tessellation” in at least some embodiments herein is defined as the process of creating a two-dimensional surface pattern using geometric overlap without overlap and without gaps. However, it should be noted that the tessellation pattern is not limited to the diamond-shaped tessellation pattern of the type illustrated in FIGS. As can be appreciated, multiple patterns based on squares, rectangles and triangles can be used. Although a regular pattern is suggested in the drawings, it is advantageous to have a randomly distributed pattern in certain cases. In one embodiment, elements of different sizes and geometries can be used in a given pattern. There are many possible schemes. The element has an aspect ratio that is vertically or horizontally deflected. In one embodiment, a wide horizontal aspect ratio provides good horizontal resolution. As shown below, a 1.38 mm × 0.8 mm diamond gives acceptable resolution. A 1 mm square (facing the side) rather than a diamond may be more reasonable, as it is not expected to benefit from better horizontal resolution than vertical. For purposes of illustration only, the description refers to tessellated tiling based on rhombus-shaped or square-shaped elements. In one embodiment of the tessellation pattern, there is a small gap that allows electrode addressing circuitry, as described below. Examples of SBG element patterns are illustrated in FIGS. FIG. 8A shows a tiled pattern 304 that includes rectangular shapes 304A-304F having multiple vertical and horizontal dimensions. FIG. 8B shows a tiling pattern 305 known as Penrose tiling that includes elements 305A-305J. FIG. 8C shows a tiling pattern 306 based on a regular hexagon that includes elements 306A-306C. FIG. 8D shows a square-based tiling pattern 306 that includes elements 307A-306D. FIG. 9A shows a rhombus-based tiling pattern 308 that includes elements 308A-308D. FIG. 9B shows a tiled pattern 309 based on an isosceles triangle that includes elements 309A-309D. FIG. 10A shows a tiled pattern 310 based on a horizontally elongated hexagon that includes elements 310A-310C. FIG. 10B shows a tiled pattern 311 based on a rectangle having a horizontally-biased aspect ratio that includes elements 311A-311D. FIG. 10C shows a tiled pattern 312 based on rectangular horizontally elongated rhombus elements 312A-312D.

  In one embodiment, the technique used to fabricate the SBG array regularly generates features as small as 50 microns (500 dpi), so interlacing features in the manner described above is not a problem. . One important condition is that the distance between gratings of the same prescription must be small compared to the size of the eye pupil under bright conditions (assuming 3 mm in bright sunlight). In one embodiment, if this condition is met, no banding is observed. Importantly, in one embodiment where the eye moves around in the eyebox, the light lost from the band moving beyond the pupil of the eye is offset by the light obtained from another band moving into the pupil There is. The intensity variation expected from this effect is approximately ± 1% of the average luminance level, assuming that the illumination across the waveguide is uniform. The concept of band-like unevenness can be most easily understood in embodiments where the SBG element includes multiple columns. However, the basic principles apply to any type of pattern used with any of the embodiments described herein.

  In some embodiments, the image light enters only one end of the DigiLens. Each waveguide of a DigiLens generally includes two SBG layers. As will be apparent in view of the drawings and specification, in such an embodiment the layers comprise SBG arrays of the same formulation, one reversed. The image feed node is configured in two symmetrical parts and provides separate image light in opposite paths to the two holographic layers. Such an embodiment requires duplication of components and is likely to be expensive to implement.

  In some embodiments, each DigiLens bilayer waveguide is 2.8 mm thick. The SBG layers are theoretically separated by a low refractive index substrate or air gap. In one embodiment in many practical applications that require a TIR beam, the geometry cannot be supported without an air interface. Note also that the thickness of the hologram is exaggerated. In one embodiment, the grating is 3 microns thick sandwiched between substrates that are 100-200 microns thick. The thickness of the transparent electrode applied to the opposing surface of the substrate is measured in nanometers.

  FIG. 11 is a schematic cross-sectional view of a DigiLens waveguide including two layers 20, 21 in one embodiment. The layer 20 includes an SBG array 20C including elements such as a transparent substrate 20A, transparent pattern electrode layers 20B and 20F, a transparent electrode layer 20D and a second substrate 20E. The layer 21 includes a transparent substrate 21A, an SBG array 21C including elements such as transparent pattern electrode layers 21B and 21F, a transparent electrode layer 21D, and a second substrate 21E. In one embodiment, the substrates 20E and 21A are combined into a single layer.

  FIGS. 12A-12D show several examples of tessellation patterns in a region that includes SBG elements of the type labeled 1-4. Eye pupil 311 is superimposed. FIGS. 13-14 show MTF data for one particular SBG element type configured as shown in FIG. 13 at the pupil position of one eye of the display exit pupil. SBG elements are labeled by 313A-313I. FIG. 14 shows the MTF curve. In this example, the upper curve 314A is a diffraction limited MTF and the lower curve is an estimated SBG array MTF that allows aberrations. Since the rhombus shape is based on a triangle with one side = 0.8 mm, the length = 1.38 mm. This architecture is applicable to two layer (one double layer) monochrome design or a single color layer in R, G, B color design. Three laminated bilayers provide composite performance. The exit pupil 311 has a diameter of 3 mm in this embodiment.

  The DigiLens architecture corresponding to FIGS. 13-14 tiles twelve SGB elements on two monochrome SBG layers. Referring to FIG. 18, the first layer illustrated in FIG. 13 includes all horizontal (lower) tiles L1 to L4 and horizontal (center) tiles (MID, 1) and (MID, 2). Tiles. The second layer tiles all tiles U1 to U4 in the horizontal (center) tiles (MID, 3), (MID, 4) and the horizontal (upper) tiles.

  FIG. 15 shows an example of tiling using a rectangular SBG with aspect ratio deflected in the horizontal direction. Tiling pattern 315 includes element types 1-5 that are also labeled by numbers 315A-315E.

  FIG. 16 illustrates, in one embodiment, how the DigiLens tiles the FOV in the exit pupil with three successive stages forming a monochrome image. The writing of each primary color image follows a similar process. FIGS. 16A-16C show that three types of SBGs 1-3, also indicated by indicators 315A-315C, are activated. In either case, the eye pupil 311 and the exit pupil 316 are superimposed. Corresponding FOV tiles 319A-319C in the FOV space indicated by rectangle 319 are shown in FIGS. Only a few SBG elements are illustrated to simplify the understanding of the switching process. It should be noted that all of a given type of SBG element can simultaneously decouple all light due to the “lossy” coupling between the beam and the grating. In other words, the diffraction efficiency of the individual elements is modulated to extract a proportion of light from the light obtained from the waveguide beam. In one embodiment, the first element with which the waveguide beam interacts has the poorest coupling efficiency, while the element at the other end of the beam path has the strongest coupling efficiency.

  The pupil area filled with light from a given type of SBG is approximately fixed. As the eye moves from left to right, light is lost from the leftmost SBG element while being obtained at the right edge. The luminous intensity variation resulting from this effect is approximately 2% (± 1% of the average luminance level), assuming that the illumination across all elements is uniform.

  In some embodiments, the periodicity of the SBG element can lead to undesirable artifacts due to diffraction due to element aperture or homogeneous interference effects. The possibility of the latter is considered low. This is because the light propagating in the planar waveguide structure is not necessarily in phase with the light from the next aperture due to the unequal optical path length inherent in the planar waveguide structure. Thus, the light exiting each periodic aperture is expected to couple incoherently when considered across all SBG elements (even if the laser coherence length is reasonably long for a planar waveguide structure). . In the event that undesirable artifacts arise from SBG elements, the periodicity of the proposed strategy involves randomly arranging the elements.

  Multiple locations throughout the aperture of the DigiLens provide angle information to the 10 mm eyebox in a progressively different manner due to 25 mm eye relief. The point towards the left of the display does not give the angle content from the right of the FOV, and vice versa. In order to maximize optical efficiency, the DigiLens in one embodiment is optimized for the fill rate that fills the desired eyebox in the prescribed eye relief. 10A-10D show the portion of the SBG aperture that contributes to the eyebox in one embodiment.

  Not all positions across the surface of the DigiLens contribute to the pupil filling factor in the eyebox. To fill a 10 mm pupil at 25 mm (eye relief), the minimum size of the light extraction SBG is just less than 30 mm wide. However, only a very small area in the center of the DigiLens gives content at all angles, for example -15 ° ± 5 °, -5 ° ± 5 °, + 5 ° ± 5 ° and + 15 ° ± 5 °. These angular bands correspond to the light extraction SBG columns 1, 2, 3 and 4 (found for the upper (+ 10 °), middle (+ 0 °) and lower (−10 °) viewing angles, respectively). .

  FIG. 17 shows the distribution of SBG tile types for the FOV tiled pattern of 3 vertical directions × 4 horizontal directions in FIG. As shown in the drawing in this case, all twelve SBG recipes are required in the center of the FOV, while the number required is exactly one at the horizontal limit of the FOV.

  FIG. 18 shows an exemplary FOV tile pattern used to tile to 52 ° × 30 ° FOV (assuming each SBG prescription gives 13 ° × 10 °). A total of 12 different types of SBG prescriptions include “UP”, “MIDDLE” and “DOWN” elements for vertical tiles and 4 for each of the vertical tiled SBG tiles (labeled 1-4). Need to be given to include two horizontal tiling recipes. Each type of SBG is represented by more than one SBG element. Therefore, in order to view the FOV tile in [UP, 1], in this embodiment, it is necessary to continuously activate each element “1” of each column group “UP”.

  19-23 illustrate SBG patterns corresponding to each tiled area defined in FIGS. 17-18. In any case, a single layer pattern and two overlapping patterns for the on-SBG type are illustrated. In this embodiment, a square element is assumed. FIG. 19 shows patterns corresponding to regions 1 and 7 (3-tile type). Two layers are indicated by 326, 327. Each layer includes type 1 elements 326A, 327A and spaces 326B, 327B (for occupation by other types of elements). In this case, one layer achieves an aperture filling factor of 33% and one double layer achieves an aperture filling factor of 66%. FIG. 20 shows patterns corresponding to regions 2 and 6 (6 tile types). Two layers are indicated by 328, 329. Each layer includes type 1 elements 328A, 329A and spaces 328B, 329B. In this case, one layer achieves an aperture filling factor of 16.7% and one double layer achieves an aperture filling factor of 33%. FIG. 21 shows patterns corresponding to regions 3 and 5 (9 tile types). Two layers are indicated by 330,331. Each layer includes type 1 elements 330A, 331A and spaces 330B, 331B. In this case, one layer achieves an aperture filling factor of 11.1% and one double layer achieves an aperture filling factor of 22.2%. Finally, FIG. 22 shows a pattern corresponding to region 4 (12 tile type). The two layers are indicated by 332, 333, each layer including type 1 elements 332A, 333A and spaces 332B, 333B. In this case, one layer achieves an aperture filling factor of 8.33%, and one double layer achieves an aperture filling factor of 16.7%.

  The resulting composite pattern 340 is shown in FIG. An example of a single SBG type coverage in the three-layer waveguide 341 is shown in FIG.

  FIGS. 25-26 show SBG patterns for each layer of a two-layer waveguide in one embodiment.

  A typical estimate of the human vision limit is about 1 arc min / line pair = 60 cyc / degree, which is a generally acceptable performance limit, equivalent to 3.4 cyc / mr. This can be achieved by standard vision under luminance conditions where the pupil of the eye is contracted to 3 mm in diameter. The eye is a restricted photoreceptor. The cone space in the fovea can be as small as 2.5 μm, equivalent to 60 cyc / degree. With large pupil apertures, eye performance is significantly degraded by aberrations of the eye. At about 3 mm, the eye performance approaches the diffraction limit. Note that the diffraction limited cutoff at 532 nm for an f / 5.6 eye (3 mm pupil where f = 17 mm) is about 320 lp / m, significantly higher than the retinal limit. The eye is therefore a density-restricted photoreceptor in this example. Considering this, if the eye pupil or the display that restricts the eye pupil is larger than 0.75 mm (equivalent to a 1.4 cyc / mr cut-off), the blur spot size in the retina is not affected. This establishes a minimum aperture requirement for the display. A 12 μm pitch LCoS microdisplay with 4H × 3V tiles can yield 2560H × 1440V pixels, with each tile having 640H × 480V pixels, but over 52 degrees H × 30 degrees V. The display projection magnification from the micro display to the retina is approximately twice. Therefore, the angular size of the micro display pixel in the eye is 6.0 μm when the display Nyquist frequency in the retina is 83 cyc / mm (1.4 cyc / mr). Image sharpness can be evaluated as sharpness when the contrast is maximum at the 1/2 Nyquist limit (that is, about 40 cyc / mm in the following plot showing the image quality at the retina).

  Addressing the concern that the periodic structure of the color waveguide SBG layer acts as a diffraction grating. Many of the potential diffraction artifact sources in color waveguides, such as high-order diffraction, zero-order beams in the waveguide, and apertures in SBG elements, are minimized (or even eliminated), and when examined closely, SBG Is a volume Bragg grating, and in one embodiment, higher orders are not supported, as seen for blazed or thin gratings. The absence of higher order minimizes (or even removes) ghost images. In one embodiment, within the waveguide light, the light that continues to be guided (in the lossy waveguide) does not “see” the output aperture of the tile. Therefore, there is no increase in the diffraction order in the beam through the waveguide. The light output from different SBG element apertures is not in phase (possibly apart from the unique case). The light path varies as a function of viewing angle. Therefore, it is reasonable to expect the output from the aperture to be out of phase and hence incoherent. Therefore, diffraction artifacts are not expected.

  Early concerns about the periodic structure were based on a column width of 50 μm. The size of the new SBG feature is now in the range of 800 μm to 1380 μm. The diffraction angle predicted from the grating equation is extremely small. For example, for a 50 μm feature with an input angle of 52 °, the diffraction angle is 1 degree (equivalent to 74 pixels). For a 1000 μm feature with an input angle of 52 °, the diffraction angle is reduced to 0.05 ° (3.7 pixels). In the very worst case in this embodiment, a diffractive ghost appears as a near-objective flare, for example when it appears under the condition of a very bright object against a dark background, and is a double image that is well separated from the original image. As does not appear.

  Although a speckle remover can be incorporated into the IIN to overcome laser speckle, there is a high degree of rationality that the design can be expected to have speckle removal. There should be phase diversity across the output SBG aperture. Polarization diversity further aids in speckle removal and therefore minimizes the effects on any diffraction artifacts from the structure. A further safety measure is that it is not essential to have a straight edge in the SBG aperture, the edge being in a pattern that randomly places any artifact.

  Several factors affect the design layout. In order to maximize the pupil filling factor, the tessellation limit needs to be taken into account. Importantly, by having 3, 6, 9 and 12 tiles for each pattern on the two single singular double layers, any position in the display exit pupil relative to the 3 mm diameter projected eye pupil This is the point that the maximum pupil filling rate condition needs to be created. The offset between the two layers of SBG patterns need not have a non-integer offset with respect to the tessellation pattern design in x or y. In one embodiment, the x offset actually results in 1/2 pixel on one side or the other side of a region, and then requires ITO addressing for the 1/2 pixel of that area alone. In one embodiment, this is better avoided to maintain a uniform addressing pitch. In one embodiment, the y offset of the pattern similarly requires 1/2 pixel vertical addressing. Similarly, it is desirable to avoid this. It is acceptable to have a ½ pixel offset in y to maximize coverage, but in this case all patterns need to have a ½ pixel offset in the same direction. In one embodiment, all 12 tile types are used in each double layer. However, the maximum tile type fill factor is obtained for 9 tile types over 2 layers. For example, it may be necessary to configure 6 tile types and 3 tile types on two layers. For example, in one embodiment, consider a region where three horizontal tile types fill the eye pupil for a single vertical tile band. It should be noted that the other layers of the plurality of double layers address the other two vertical tile bands. Layers 1 and 2 both contain the same tile, but achieve the desired pupil fill factor in the offset array. A single tile has dimensions (H, V) = (0.8 * sqrt (3), 0.8) = (1.386, 0.8). The offset on a single layer of one tile type is given by (dx, dy) = (0, 3V). The offset of layer 1 with respect to layer 2 is given by (dx, dy) = (0.5H, 1.5V) = (0.693, 0.4). In the following analysis, a 1 mm × 1 mm square is used to simplify optical modeling. However, the principle is the same regardless of the shape. However, it should also be noted that certain shapes are preferentially filled.

  FIGS. 27-29 illustrate some embodiments of an IIN that includes an input image generator. The input image generator includes a diode laser module 34, a coupling prism 34A, an SBG beam splitter layer 35 sandwiched between substrates 35A and 35B, a micro display module 38, an optical waveguide 41 including surfaces 42A and 42B, an input coupling unit, a holo Includes graphic objectives, spacer half-wave plates, and holographic objectives.

  Advantageously, in one embodiment, the IIN provides a telecentric (slightly projected) pupil. This allows good frame control and good filling of the vertical beam expander by the pupil.

  FIG. 28A is a cross-sectional view illustrating coupling from an input image node to a DigiLens via VBE in one embodiment. FIG. 28B shows a detailed ray trace of the embodiment of FIG. 28A. The VBE may or will actually include grating extracted light that is lossy from the beam over a distance corresponding to the height of the DigiLens. At the objective lens input, the light is ordered and the light across the pupil is arranged in a tight viewing angle bundle. At the distal end of the VBE, the bundles are further distributed by different numbers of light bundles having different viewing angles. At the objective lens end, the pink ray with the highest waveguide angle is furthest from the rest of the VBE waveguide. The steepest ray (yellow) in the waveguide starts from the left end. This helps to keep the passive input coupler (and VBE thickness) down. At the distal end (fully left), the coupling from VBE to the waveguide is hindered by the loss of order found at the input. To avoid doubling the waveguide thickness, in one embodiment, a 50/50 active coupler is used in the coupling stage with the VBE's DigiLens.

  FIG. 29 is a plan view of a digital lens and VBE. This shows how VBE is separated into two switchable elements. This reduces the waveguide thickness. Each DigiLens double layer waveguide is 2.8 mm thick. Without the switch, the thickness doubles and the total waveguide thickness increases from about 10 mm to about 18 mm. FIG. 10 shows the rays traced from VBE to the DigiLens.

  Some examples given here need to be well adapted to the substrate waveguide optics. First, component costs are reduced. Various holographic optical elements involve optical complexity. Once non-repetitive engineering (NRE) associated with creating a set of masters is completed, the replication costs are relatively small compared to the iterative material costs associated with separate refractive components. Second, assembly time is reduced. Not only is the number of parts reduced, but the assembly process is considerably faster. Multiple planar structures can be stacked together cost-effectively with very high optical precision by using alignment criteria. Compared to the work of making a piece parts assembly to meet strict standards, manual work is also greatly reduced. Third, optical precision is increased. One of the biggest challenges in designing a new optical design is to control increasing tolerances for piece parts, mechanical housings and assembly procedures. With respect to holographic optical elements (HOE), the “golden standard” can be assembled by senior engineers acquired by the HOE master during the NRE phase and this level of quality. In addition to the fact that optical alignment of the HOE is performed with high precision, individual HOEs have tolerances for variation in alignment. Therefore, the overall yield of high quality devices is quite high. Finally, size and weight are greatly reduced by this monolithic design where the durability of the entire subsystem exists.

  One important performance parameter is the see-through transparency of the display. Variable factors affecting permeability are the ITO coating (0.995), the AR coating (0.99) and the absorption of the substrate and holographic layer. There is also a Fresnel loss at the interface between the waveguide and the low index adhesive layer. In one embodiment, the desired transmission for a color display with an objective lens greater than 90% is greater than 70%. Assuming 3 waveguides per display and 2 substrates per waveguide, the calculated transmission is 93%, which fits the specified objective. In one example, the design described herein uses a 100 micron glass substrate. With three waveguides and three substrates per waveguide (note that two holographic layers require three substrates), the total display thickness of the color display is still less than 1 mm. The thickness of the holographic layer (including the coating) is negligible. This is because each contributes only 4-5 microns to the total thickness. Since weight is always a problem, this is also an important feature of the embodiments described herein. In one embodiment where the substrate comprises plastic, the weight is further reduced.

  In one embodiment, the SBG operates in a reverse mode that diffracts when a voltage is applied and remains optically passive in all other cases. The SBG is implemented as a continuous SBG thin layer separated by a thin substrate layer (as thin as 100 microns) as shown. Ultimately, the design goal is to use a plastic substrate with a transmissive conductive coating (as a replacement for ITO). Plastic SBG technology suitable for this application is being developed in a parallel SBIR (Small Business Innovation Research) project. In this example, this is a planar monolithic design that takes full advantage of the assets of narrowband laser illumination with monolithic holographic optics.

  By configuring the SBG as a monochrome layer, a holographic optical instrument and SBG beam splitter technology can be used to provide a flat, solid state and precision aligned display. This minimizes the need for bulky refractive optics. The display resolution is limited only by that of the LCoS panel.

  The design can be scaled for large FOVs by interlacing many tiles in each layer and / or adding new layers. Similarly, pupil, eye relief, and FOV aspect ratio can be tailored to suit the application. The design can also be scaled down for small FOVs.

  30A-30B illustrate a scheme for polarization recycling used with at least some examples described herein. This is significant in the event that polarization is not maintained by the SBG light extraction waveguide based on the properties of the SBG material (current or future developed) or if a polarization rotation component is intentionally introduced into the waveguide. is there. Specifically, when linearly polarized light is input into a DigiLens waveguide (ie, light is coupled from VBE into the waveguide) and when light is converted to a mixture of S and P polarized light, a thin DigiLens waveguide is used. Can be used. As a result, the waveguide can be reduced to a half thickness. FIG. 30A shows a waveguide 252 in which the input rays 354A, 354B are directed into the TIR path labeled by the coupling grating 353 by 355A, 355B. The light is in any polarization. However, P-polarized light is desirable for the SBG input grating in one embodiment. The combined grating aperture is A. For illustrative purposes only, the TIR angle is selected to be 45 °. As a result, after the first TIR bounce, the waveguide thickness required for the limited input beam to border the edge of the coupled grating is A / 2.

  Referring to FIG. 30B, a waveguide 356 includes first and second gratings 357A and 357B arranged adjacent to each other, a half-wave film 357C sandwiched between the waveguide and the first grating, An input coupling optical device including a polarization beam splitter (PBS) film 357D sandwiched between the waveguide and the second grating is included. PBS is designed to transmit P-polarized light and reflect S-polarized light. Again, the TIR angle is selected at 45 ° for illustration purposes only. Input P-polarized collimated light 358A, 358B is routed through the first grating and half-wave film (HWF) to provide S-polarized light 359A, and through the second grating and PBS to provide P-polarized light 359C, 359D. Coupled into the waveguide. Comparing the example of FIGS. 30A and 30B, it is clear that in the second example, the input coupling aperture can be equal to two TIR bounce lengths due to polarization recovery by HWF and PBS. In the example of FIG. 30A, the input pair cannot be longer than one TIR bounce. This is because light is diffracted so as to go out of the waveguide and go downward due to the mutual dependence of the grating. One advantage of the embodiment of FIG. 30B is that the waveguide thickness can be reduced by 50%. That is, for a coupler length equal to A, the waveguide thickness (for 45 ° TIR) is A / 4. At this time, in some embodiments, S light and P light in the waveguide are not separated. Typically, the input light is divergent, so S and P light are rapidly spatially mixed. However, if the waveguide rotates the polarization because of many P light extractions, there are more S to P conversions than P to S conversions. That is, a net gain is provided. Polarization rotation results from the reflection properties of the waveguide wall and from the birefringence of the holographic material in which SBG is used. In one embodiment, polarization rotation is provided by applying a quarter wave film (QWF) to the bottom surface of the waveguide. HWF and QWF are about 0.125 mm thick. A typical adhesive layer is about 75 microns. Thus, in some embodiments, the contribution of the polarization control film to the overall waveguide thickness is not significant. In certain cases, the film can be immersed in an adhesive layer used for lamination purposes.

  FIG. 31 illustrates counter-propagating waveguides used in some embodiments. The waveguide includes adjacent thin grating layers 51A, 51B of the same but opposite formulation sandwiched between substrates 52A, 52B. Waveguide light 362 propagating from left to right interacts with grating 51A to provide continuously extracted light 360A-360C, resulting in an expanded output beam 360. Waveguide light 368 propagating from right to left interacts with grating 51B to provide continuously extracted light 361A-361C, resulting in an expanded output beam 361. Note that a small amount of light that is not extracted from the left / right propagation direction interacts with the opposing grating, and is diffracted in the direction opposite to the expanded beams 360, 361 and extracted from the grating, as indicated by the rays 363-366. .

  FIG. 32 illustrates the use of a beam splitter to achieve uniformity in the waveguide of one embodiment. This principle applies in both extension axes. As a further improvement, a beam splitter offset is used for the waveguide (ie, offset from the midpoint of the waveguide rather than midway between the waveguide surfaces to maximize uniformity after multiple bounce interactions). A still further improvement consists in using different reflectivities in the beam splitter to optimize and adjust the beam mixing. Without being bound by any particular theory, by changing the reflectivity% of the beam splitter to something other than 50/50, or by changing the transmission / reflection split along the B / S length The pupil filling factor can be homogenized and optimized. For example, in FIG. 32, the waveguide 353 includes a beam splitter layer 352. In some embodiments, the beam splitter can be provided using a thin film coating. A TIR beam such as 370 then undergoes a beam split. As a result, as shown by the rays 371 to 373, between the upper wall and the lower wall of the waveguide, between the upper wall of the waveguide and the beam splitter, and between the beam splitter and the lower wall of the waveguide. Waveguide is generated.

  An IIN stopper is formed by controlling the profile of the input illumination. In at least some embodiments, there is no hard physical stop on the projection optics. The advantages of projected stoppers include a reduction in waveguide thickness. The stopper is projected midway above the VBE to minimize the aperture diameter in the VBE. This minimizes the aperture width of the VBE relative to the DigiLens waveguide coupler (for example, reducing the width of the first axis expander limits the thickness of the second axis expansion optical instrument).

  FIGS. 33-36 show details of the ITO addressing architecture used in the DigiLens in some embodiments.

  FIG. 33 illustrates a method for reducing the number of tracks in a given ITO layer. This method uses double-sided ITO addressing and superpixel addressing to reduce the number of tracks by approximately 1/3. The pixels presented to the first group 350 include 3 unit by 1 unit dimension elements, such as those labeled by 350A, 350B, and 1 unit by 1 unit dimension elements, such as those by 350C-350H, The second overlapped inversion group 351 includes the same pixel geometry as indicated by 351A-351G.

  Figures 34-36 show how the interleaving of electrode wiring tracks is used to allow addressing (switching) multiple different tessellation types in a 2D electrode structure. FIG. 34 shows a wiring scheme used in an embodiment in which electrode elements such as 401 are connected by tracks 402-404. FIG. 35 shows a wiring scheme in another embodiment having the electrodes 407-409 and track portions 410, 411 shown. FIG. 36 shows in detail the electrodes and tracks of the embodiment of FIG. Elements and tracks are indicated by numbers 421-434.

  The electrode architecture benefits from reduced component complexity by using the same pattern technology and flip symmetry resulting in a sufficient addressing network. This is not required in the design work, but limits the number of parts that require design and handling.

  In one embodiment, an incremental reflection profile beneath the SBG layer is used to control (or assist) the grating DE (diffraction efficiency) variation along the length (usually using refractive index modulation to form the SBG grating. Achieved). This is useful when a low percentage of light is extracted at the first bounce, but a high percentage is extracted at the other end of the dilator.

  In one embodiment, a 1D extension engine is used to double the input power and / or minimize the 1D aperture width.

  In one embodiment, the display is configured as a “visor”. The color waveguide draws a curve in at least one plane. In general, such embodiments have a large (30 mm) eye relief and a large exit pupil. A large exit pupil reduces (or even eliminates) the need for IPD adjustment. 37A to 37B are a schematic plan view and a side view of a curved visor including a digital lens 71 and optoelectronic modules 70A and 70B on both sides. One module contains the IIN. The second module includes auxiliary optical equipment and electronic equipment.

  FIG. 38 shows in detail the DigiLens of the curved visor in one embodiment. The digital lens includes a plurality of laminated waveguides each including SBG arrays 73A-73C. In this case, the three SBG layers are isolated from each other by the cladding layers 72A to 72D. The ray path is indicated by 381A-381C. In the embodiment of FIG. 39, the SBG layer is laminated without a cladding layer to form a single waveguide structure. The ray path is indicated by 382A-382C.

  In one embodiment shown in FIG. 40, the visor digi lens takes the shape of facet plane elements 76A, 76B. This can make the waveguide planar. As shown in the insertions B and C, gratings 77A and 77B are provided at the optical interface 77 between the facets. As a result, the beam angle is controlled to ensure efficient coupling between the waveguide image light and the SBG array element. The gratings 77A and 77B are Bragg gratings. In one embodiment shown in FIG. 41, a facet digi lens including planar facets such as 76A, 76B is embedded in the curved optical waveguide 79.

  The embodiments depend on monochrome waveguides. However, as will be apparent in view of this specification, in alternative embodiments, the waveguide may operate in more than one color. Such an embodiment involves a complex IIN design.

  In at least some embodiments, the multilayer architecture described herein cannot be used with conventional holograms. This is because they interfere with each other. Thus, to overcome this challenge, SBGs can be used that can be switched to transparent to allow time-domain integration of viewing angles.

One embodiment described herein relates to an HMD such as one having the following specifications:
a) 180 ° see-through visibility,
b) Full color
c) Viewing angle 52 ° × 30 °,
d) Eye box 30mm x 30mm,
e) Resolution 2560 × 1440,
f) Snellen vision standard,
g) Eye relief 30mm,
h) Universal IPD,
i) binocular, and j) polycarbonate optics.

  One important feature of at least some of the embodiments described herein is to provide see-through benefits. This is very important in private see-through displays, such as for automotive, aircraft and other transportation applications, security related applications, building interior signs, and heads-up displays for many other applications. In addition to holographic brightness enhancement films or other narrow band reflectors attached to one side of the display for the purpose of reflecting only the display illumination wavelength light, the see-through display is invisible (and therefore safe) in the opposite directional field of view. You can also The reflected display illumination is effectively mirrored and therefore blocked in one direction. This is desirable for transparent desktop display applications in customer or personal interview settings, which are typical in bank or asset service settings.

  Although some of the above embodiments describe wearable displays, it will be appreciated that in any of the above embodiments, the eyepiece and retina may be replaced with any type of imaging lens and screen. . Any of the embodiments described above can be used in either a direct viewing or virtual image display. Possible applications range from small displays such as those used in viewfinders to large area public information displays. The above embodiment is also used for applications where a transparent display is desired. For example, some embodiments are used in applications where display images are superimposed on the background, such as head-up displays and teleprompters. Some embodiments are used to provide a display device that is located at or near the internal image plane of the optical system. For example, any of the embodiments described above can be used to provide a symbol data display for a camera viewfinder. After the symbol data is projected onto the intermediate image plane, it is enlarged by the viewfinder eyepiece. One embodiment applies to binocular or monocular displays. Another embodiment is also used for a stereoscopic image mountable display. Some embodiments are used in rear projection televisions. One embodiment applies to aviation, industrial and medical displays. There are multiple applications in entertainment, simulation, virtual reality, training systems and sports.

  Any of the above-described embodiments that use laser illumination can incorporate a speckle remover device that removes laser speckle located at any point in the illumination path from the laser path to the eyepiece. Advantageously, the speckle remover is an electro-optical device. Preferably the speckle remover is based on an HPDLC device.

References

The following patent applications are hereby incorporated by reference in their entirety:
US Provisional Patent Application No. 61 / 627,202, also referred to by the applicant's package number SBG106, with the name “WIDE ANGLE COLOR HEAD MOUNTED DISPLAY”, filed October 7, 2011, filed by the inventor.
International application date July 22, 2008, international application number US2008 / 001909 with the name “LASER ILLUMINATION DEVICE”,
International application No. US2006 / 043938 with the name “METHOD AND APPARATUS FOR PROVIDING A TRANSPARENT DISPLAY”,
International application GB2010 / 001982 with the name “COMPACT EDGE ILLUMINATED EYEGLASS DISPLAY”,
International application date April 26, 2010, international application GB2010 / 000835 with the name “Compact holographic edge illuminated eyeglass display”,
Filing date November 2, 2010, international application GB2010 / 002023 with the name "APPARATUS FOR REDUCING LASER SPECKLE",
Filing date November 4, 2005, US patent application Ser. No. 10 / 555,661, entitled “SWITCHABLE VIEWFINDER DISPLAY”,
Filing date September 28, 2010, US Provisional Patent Application No. 61 / 344,748, entitled “Eye Tracked Holographic Edge Illuminated Eyeglass Display”,
US provisional patent application whose name is "IMPROVEMENTS TO HOLOGRAPHIC POLYMER DISPERSED LIQUID CRYSTAL MATERIALS AND DEVICES" by the present inventor, which is currently not available but is referred to by the applicant's package number SBG104,
Application date: June 16, 2011, US Provisional Patent Application No. 61 / 457,835, entitled “HOLOGRAPHIC BEAM STEERING DEVICE FOR AUTOSTEREOSCOPIC DISPLAYS”,
International application date June 22, 2008, international application number US2008 / 001909 with the name “LASER ILLUMINATION DEVICE”,
Filing date of the applicant on November 2, 2010, international application GB2010 / 002023 with the name “APPARATUS FOR REDUCING LASER SPECKLE”,
US Provisional Patent Application No. 61 / 573,121, also referred to by the applicant's package number SBG105B, dated September 7, 2011, filed by the present inventor and named “METHOD AND APPARATUS FOR SWITCHING HPDLC ARRAY DEVICES” ,
International Application Date Apr. 26, 2010, International Application No. GB2010 / 000835 of the name “COMPACT HOLOGRAPHIC EDGE ILLUMINATED EYEGLASS DISPLAY” (and also referred to by the applicant's bag number SBG073PCT), and the name of the inventor This is a US provisional patent application of “IMPROVEMENTS TO CONTACT IMAGE SENSORS” that is currently not available but is referenced by the applicant's bag number SBG100.

Micro tessellation

  One set of embodiments uses micro tessellation. The performance of a micro tessellation grating in the background of a switchable Bragg grating digital lens (DigiLens®) waveguide device is explored below. Tessellation is a pattern of repetitive shapes that fit together without gaps. The use of the term “tessellation” refers to a singular element of a tessellation pattern. In the practical application of tessellation associated with DigiLens® devices, tessellation also means creating multiple patterns without substantial gaps between tessellation elements. That is, here, the overall aperture filling factor coefficient is high.

  A tessellation element is a region (aperture) of one or more diffractive gratings that becomes a switchable diffraction grating (SBG). Tessellation diffracts light simultaneously across all regions of the tessellation. The diffractive grating is switchable or non-switchable.

  Microtessellation: This is a small tessellation that exists within a large main tessellation element. Multiple micro tessellations within one main tessellation have different grating prescriptions. A plurality of micro tessellation elements present in one main tessellation element all diffract light simultaneously. Tessellation performance and its impact on MTF are described in earlier literature. There, a single grating is written in the tessellation.

Micro tessellation in the main tessellation structure

  Interesting performance considerations are MTF (resolution) and viewing angle uniformity.

  In a tiled substrate waveguide (SGO), there is a single viewing angle in the waveguide. At any given time instant, it has viewing angle information for a portion of the overall viewing angle. In the case of an ophthalmic display, this is part of the projected field of view taken from the SGO. The light extraction grating needs to extract this viewing angle content so that the eye can see this viewing angle information across the eyebox. Preferably, the eye pupil at any position within the eyebox is extracted with the same radiant flux for each viewing angle and for all viewing angles. Early research has recognized that large tessellation results in excellent MTF (resolution) performance, and the smaller the tessellation, the more uniform the viewing angle irradiance at the eye pupil. is there. The light extraction grating angle band causes a decrease in output light along with the viewing angle. The minimum tessellation size that provides sufficient resolution depends on the required system resolution. However, a minimum tessellation aperture size of 0.5 mm to 1 mm in width (or diameter) should support a resolution of approximately 0.7 to 1.4 lp / mr if a large aperture is preferred in one embodiment. . This particularly affects high spatial frequency performance.

  Tessellation is a region of a light extraction grating that, when in a diffractive state, simultaneously diffracts light at all locations in the tessellation aperture region. The region within the tessellation includes one grating recipe or multiple grating recipes. This multiple-grating prescription is either by multiplexing the gratings (multiple grating prescriptions share the same area of tessellation) or by having a spatially distinct region of the tessellation where only a single grating is written. Achieved. Micro tessellation is a small tessellation that is switched simultaneously with other small tessellation areas. Spatially distinct micro tessellations (μT) are probed as follows.

  The μT grating is designed to have an angular band that overlaps with the neighboring μT (at viewing angle). Modeling micro tessellation for a given viewing angle in one embodiment is described below. One case to consider is FoV superposition of micro tessellation that allows different viewing angles to be output at different locations. Another case to consider is the equal irradiance of the eye pupil for a given viewing angle from multiple micro tessellations. Since there is also a viewing angle that outputs light evenly from multiple micro tessellations, the same irradiance of the eye pupil can be obtained. It is assumed that there is now a microtessellation that has little or no irradiance in the eye pupil. A top hat model is appropriate to model this case.

  The uneven irradiance of the eye pupil for a given viewing angle from multiple micro tessellations is investigated. In order to model this case, it is necessary to model the unequal aperture weighting. For any given singular viewing angle, the output from microtessellation to microtessellation will not be a smooth function, but rather a stepped function. This is shown in the following spatial distribution plot.

  The following modeling first evaluated the case of uniform irradiance for aperture fill rates of 25%, 50% and 75%. Most of the viewing angle cases are not top-hats and need to be evaluated with typical viewing angle weighting functions for different micro tessellations.

  A typical angular distribution is shown in FIG. 42A. The corresponding spatial distribution is shown in FIG. 42B. In case A, the top hat function for this viewing angle gives an aperture fill factor of 50%. In case B, the tiles have different weights. Therefore, the aperture is not a top hat function. Note that the micro tessellation need not be the square or order shown and can have any shape or order, such as a 2D distribution.

  Structured and random sequences were investigated. The following figure shows a non-random regularly repeating micro tessellation pattern.

  FIG. 43 illustrates an MTF curve (FIG. 43A) and a 3D layout diagram. FIG. 43B shows the effect of 50% aperture fill. The aperture is 50 μm with a pitch of 100 μm and the pupil of the eye is 3 mm. Only an aperture of 10 μm pitch (fill factor 25%) and green light (532 nm) with a pitch of 40 μm was assumed. Note the high modulation in the resulting frequency space. FIG. 44 shows the effect of an aperture filling factor of 25%. The aperture is 10 μm with a pitch of 40 μm, and the pupil of the eye is 3 mm. MTF and 3D layout plots are given. The aperture is 10 μm with a pitch of 40 μm (filling factor 25%). Green (532 nm) is assumed. FIG. 45 shows the effect of an aperture filling rate of 50%. The aperture is 125 μm with a pitch of 250 μm, the pupil of the eye is 3 mm, and the MTF plot (FIG. 45A) and footprint diagram (FIG. 45B) are used. A stripe aperture of 125 μm with a pitch of 250 μm (fill factor 50%) and green (532 nm) is assumed. A non-random regular periodic structure shows an instantaneous drop in MTF over the entire range of angular frequency interest. Typically 1.4 cyc / mr.

  Next, a random micro tessellation pattern was considered. The result from the periodic aperture function indicates a “hole” in the MTF. In the following, the randomization of eye pupil filling using micro tessellation will be investigated. A fill factor of 25%, 50% and 75% tessellation is considered. For this initial analysis, it was considered that the tessellation would be 100% of the eye pupil. In the latter case, a 1 mm square tessellation is considered that encompasses micro tessellation with a 3 mm eye pupil.

  The following example shows the characteristics of a 50 micron micro tessellation. FIG. 46A is a footprint diagram showing the effect of an aperture filling factor of 75% for micro tessellation of 50 μm on the eye pupil of 3 mm. FIG. 46B is an MTF plot showing the effect of 75% aperture fill of 50 μm micro tessellation on the eye pupil 3 mm. FIG. 47A is a footprint diagram showing the effect of 50% aperture fill factor of 50 μm micro tessellation on the eye pupil 3 mm. FIG. 47B is an MTF plot showing the effect of 50% aperture fill factor of 50 μm micro tessellation on the eye pupil 3 mm. FIG. 48A is a footprint diagram showing the effect of an aperture filling factor of 25% for a micro tessellation of 50 μm on a 3 mm pupil of the eye. FIG. 48B is an MTF plot showing the effect of 25% aperture fill for 50 μm micro tessellation on the 3 mm pupil of the eye.

  Next, 125 micron micro tessellation was investigated. FIG. 49A is a footprint diagram showing the effect of a micro tessellation of 125 μm and an aperture filling factor of 75% for an eye pupil of 3 mm. FIG. 49B is a footprint diagram showing the effect of a micro tessellation of 125 μm and an aperture filling factor of 75% for an eye pupil of 3 mm. FIG. 50A is a footprint diagram showing the effect of micro tessellation of 125 μm and an aperture filling rate of 50% for an eye pupil of 3 mm. FIG. 50B is a MTF plot showing the effect of micro tessellation of 125 μm, aperture fill factor 50% of 3 mm eye pupil. FIG. 51A is a footprint diagram showing the effect of a micro tessellation of 125 μm and an aperture filling factor of 25% for an eye pupil of 3 mm. FIG. 51B is an MTF plot showing the effect of micro tessellation of 125 μm, aperture fill factor of 25% for an eye pupil of 3 mm.

  Next, a micro tessellation of 250 microns was investigated. FIG. 52A is a footprint diagram showing the effect of micro tessellation of 250 μm, aperture filling ratio of 75% of eye pupil 3 mm. FIG. 52B is a footprint diagram showing the effect of micro tessellation of 250 μm, aperture filling ratio of 75% of eye pupil 3 mm. FIG. 53A is a footprint diagram showing the effect of a micro tessellation of 250 μm and an aperture filling ratio of 50% for an eye pupil of 3 mm. FIG. 53B is an MTF plot showing the effect of micro tessellation of 250 μm, aperture fill factor 50% of eye pupil 3 mm. FIG. 54A is a footprint diagram showing the effect of micro tessellation of 250 μm and aperture filling factor of 25% for an eye pupil of 3 mm. FIG. 54B is an MTF plot showing the effect of micro tessellation of 250 μm, aperture fill factor of 25% for an eye pupil of 3 mm.

  Tessellation and microtessellation smaller than the diameter of the eye pupil were also investigated. FIG. 55A is a footprint diagram showing the effect of 1 mm tessellation using a 3 mm diameter pupil of the eye resulting in a 50% fill rate of 125 μm micro tessellation. FIG. 55B is an MTF plot showing the effect of 1 mm tessellation with a 50% fill rate of 125 μm microtessellation using an eye pupil diameter of 3 mm. FIG. 56A is a footprint diagram showing the effect of 1.5 mm tessellation resulting in a 50% fill rate of 125 μm micro tessellation using an eye pupil diameter of 3 mm. FIG. 56B is a footprint diagram showing the effect of 1 mm tessellation resulting in 50% filling of 125 μm micro tessellation using a 3 mm diameter pupil of the eye. FIG. 57A is a footprint diagram showing the effect of 1 mm tessellation using a 3 mm diameter pupil of the eye, resulting in a 50% fill rate of 125 μm micro tessellation. FIG. 57B is an MTF plot showing the effect of 1 mm tessellation resulting in 50% fill rate of 125 μm micro tessellation using a 3 mm diameter pupil of the eye.

  A spatially random variable transmittance aperture was investigated. The first step is to check the validity of the model, ie the change from UDA (User Defined Aperture) to Bitmap Grayscale Transparent Aperture. In a 3 mm diameter eye pupil, the horizontal stripe spans an aperture of 1.5 mm (125 μm μT).

  In the following, modeling techniques are compared. An implementation model using a UDA (user-defined aperture) and a bitmap model as a transparent aperture. Here, the bitmap level is binary. Since the predicted MTF results are the same, the modeling tools are equivalent. FIG. 58A shows a MTF plot of UDA. FIG. 58B shows a bitmap aperture function.

  FIG. 59 shows 1.0 mm tessellation using 125 μm micro tessellation randomly positioned with variable transmission and 3 mm eye pupil. By using variable aperture transmittance, the model can be improved to better represent the case of the non-top hat model (which is the majority of tessellation). The DE values 0%, 50% and 100% are equivalent to the viewing angle case shown in FIG. 59A.

  Note that this represents the widest spatially possible case of the three superimposed gratings. That is, the viewing angle is output by 75% of the main tessellation area (despite the 50% contribution from the two micro tessellations). Four tile types are represented here. The transmittance values were 50%, 100%, 50%, and 0%. The aperture of the micro tessellation is a 125 μm square. The grid was 8x8 pixels. Thus, the tessellation aperture is a 1 mm × 1 mm square.

  FIG. 60 is an MTF plot showing the effect of 1.0 mm tessellation using 125 μm μT randomly positioned with variable transmission and 3 mm eye pupil. Note that the spatial frequency in the upper enclosed region is between predictions shown in the figure related to the top hat prediction for the pixel 125 μm with the aperture filling ratios of 50% and 75%. The high spatial frequency shown in the lower enclosed area is most affected by the main tessellation shape. The reader refers to the diagram shown for an aperture fill factor of 50%. It should also be noted that there is an improvement in MTF for 75% aperture fill.

  Referring now to FIG. 61, 1.5 mm tessellation using 125 μm micro tessellation randomly positioned with variable transmission and 3 mm eye pupil was considered. Four different tile types are represented in FIG. The transmittance values were 50%, 100%, 50%, and 0%. The aperture of the micro tessellation was a 125 μm square. The grid is 12 × 12 pixels. Thus, the tessellation aperture is a 1.5 mm × 1.5 mm square.

  FIG. 62 is an MTF showing the effect of 1.5 mm tessellation using 125 μm micro tessellation randomly positioned with variable transmission and 3 mm eye pupil. It should be noted that high spatial frequencies are most affected by the main tessellation shape. Therefore, increasing the basic tessellation from 1.0 mm to 1.5 mm improved the high frequency response.

Summary:
a) It is necessary to consider the diffraction effect of micro tessellation.
b) The diffraction effect of micro tessellation is distinct from the diffraction effect of the basic main tessellation pattern.
c) The use of μT degrades the MTF compared to the use of singular tessellation that does not involve micro tessellation. However, due to micro tessellation, the tessellation can have a large angular band. This reduces the overall number of tessellations desired. This allows a large tessellation.
d) A regular pattern of μT causes MTF modulation that causes an unacceptable momentary drop in MTF frequency response.
e) The instantaneous drop in MTF can be averaged by spatially randomly arranging micro tessellations. It is necessary to make μT sufficiently small to allow a reasonable random arrangement. A tessellation with a ratio to μT width of about 8: 1 appears to be sufficient, but this has not been explored well.
f) The viewing angle overlap between tessellations is extremely important for successful implementation of μT. In the modeled case, the micro-tessellation ABW (angle band) is at least 1/2 of the total tessellation ABW. The greater the overlap, the better the MTF performance, as this effectively increases the available aperture for a given viewing angle.
g) Tools are established here to model trade-off cases for different grating configurations.

  Implementation of a micro tessellation structure with a spatial random array over a single tessellation provides additional design flexibility. In fact, the tessellation angle band (ABW) is improved at the expense of MTF. The conclusions indicate that random arrangement of micro tessellation features allows homogenization (approximate averaging) of MTF oscillations found in non-random patterns. Furthermore, less interesting spatial frequency MTFs can be sacrificed for improved tessellation ABW. Different cases are also considered for the associated superimposed grating. The MTF supported by micro tessellation depends on the micro tessellation size and percent overlap. The typical case ABW of superimposed tessellation needs to be considered in detail in the context of folding gratings where it is desired to support the desired architecture. Micro-tessellations with feature sizes of 50 μm, 125 μm and 250 μm are considered against the background of main tessellation elements with eye pupil sizes of 3 mm and 0.5 mm, 1.0 mm and less than 3 mm. These are practical numbers for operating with a near-eye display as a background. However, the tessellation is any size or shape and the micro tessellation is any size or shape that is smaller than the main tessellation.

  Next, illuminance uniformity analysis of the tessellation pattern was performed. Referring to FIG. 63, Case 1 with 1 mm tessellation was considered. A reference design that is filled with each overlap is shown in the figure. FIG. 63 represents a 6 layer, 12 tile, monochrome reference design. A single tile with an aperture fill factor of 50% was assumed. Further assumed were an eye relief of 17 mm, an eye pupil of 3 mm, a 6 layer monochrome reference design, a 1 mm tessellation, and an offset reference design. The unit cell is 2 × 3. The superposition generates a tiled superposition pattern as shown in FIG. For 1 mm tessellation, the highest uniformity from minimum to maximum is ± 12% at 50% aperture fill, ie uniformity variation ± 12% = 24% pp.

  FIG. 64 shows a case 1b repeated on the axis for an eye relief of 3 mm eye pupil 3 mm. Eye relief affects the spatial frequency associated with fluctuations. The larger the eye relief, the higher the spatial frequency ripple. The magnitude of uniformity is not affected. The maximum ripple is a pupil filling factor of 56.6%. The minimum ripple is a pupil filling factor of 43.4%. The uniformity is ± 13.2% and peak to peak is 26.4%.

  FIG. 65 shows Case 2 with 1 mm tessellation and optimized fill factor. The figure represents a 6-layer, 12-tile monochrome reference design with the grating position again optimized. A single tile has an aperture fill factor of 50%. A 3 mm eye pupil and 1 mm tessellation were assumed. Tessellation is spatially uniform.

  FIG. 66 illustrates Case 2 considering maximum and minimum situations. Footprint diagrams corresponding to a minimum of 45.1% and a maximum of 54.9% are shown. For 1 mm tessellation, the highest uniformity from minimum to maximum is ± 5% with an aperture fill factor of 50%, ie uniformity variation ± 10% (20% pp).

  FIG. 67 exemplifies Case 3 of a tessellation with an aperture filling rate of 50% and off-axis of 0.5 mm. FIG. 67 represents a 6 layer, 12 tile, monochrome reference design with a tessellation of 0.5 mm. A single tile, an aperture fill factor of 50% and an eye pupil of 3 mm are assumed. This calculation simulates 50% aperture fill with 0.5 mm wide tessellation. The ripple is calculated as maximum = 50.4, minimum = 49.6. The magnitude of the ripple is about ± 0.8% (1.6% PP). The measured viewing angle range was about 11 to 24 degrees. The ripple frequency is about 1 cycle for 1.25 degrees.

  FIG. 68 illustrates a case 3b with an aperture filling factor of 50% and 0.5 mm tessellation on the axis. FIG. 68 represents a 6 layer, 12 tile, monochrome reference design with a tessellation of 0.5 mm. A single tile, an aperture fill factor of 50% and an eye pupil of 3 mm was assumed. This simulates an aperture fill factor of 50% with 0.5 mm wide tessellation. The ripple was calculated as maximum = 50.9, minimum = 49.6. The magnitude of the ripple is about ± 1.5% (3% PP). The measured viewing angle range was about ± 6.5 degrees. Off-axis, tessellation is shortened, thus improving uniformity. The ripple frequency is about 1 cycle for 1.25 degrees.

  FIG. 69 illustrates an eye pupil of 4 mm, a tessellation of 0.5 mm, and an aperture filling rate of 50%. As shown in the drawing, the characteristics are a maximum of 51.97%, a minimum of 48.03%, and a ripple ± 2% (= 4% pp).

  FIG. 70 illustrates an eye pupil of 3 mm and an aperture filling rate of 33% (3 layers, 9 tile type). FIG. 70 represents a 3-layer, 9-tile, monochrome reference design with a tessellation of 0.5 mm. A single tile with an aperture fill factor of 33% and an eye pupil of 3 mm was assumed. The ripple was calculated with a maximum value = 36.9 and a minimum value = 30.4. The magnitude of the ripple is about 6.5% / 33% = ± 9.75% (= 19.5% PP). The ripple frequency is about 1 cycle for 5 degrees.

  FIG. 71 illustrates an eye pupil of 4 mm and an aperture filling rate of 33% (3 layers, 9 tiles type). A single tile, an aperture fill factor of 33% and an eye pupil of 4 mm was assumed. Ripple was calculated as maximum = 35, minimum = 30.8. The magnitude of the ripple is about 4.2% / 33% = ± 6.3% = 12.6% PP. The ripple frequency is about 1 cycle for 5 degrees.

  FIG. 72 illustrates an eye pupil of 3 mm and an aperture filling rate of 33% (3 layers, 9 tile type). A single tile, an aperture fill factor of 33% and an eye pupil of 3 mm was assumed. The calculated characteristics are: ripple maximum value 35.2%, ripple minimum value 29.7%, uniformity 5.5% / 33.3% = ± 8.25% = 16.5%.

  FIG. 73 illustrates how the unit cell forms a uniform distribution pattern.

  FIG. 74 is a recalculation of an example using an eye pupil of 4 mm and an aperture filling rate of 33% (3 layers, 9 tile type). For this, the pattern needs to have 1 × 3 unit cells with a uniform column offset of 0.5 pixels.

  A grid distribution using a uniform column 1/2 pixel offset gives a more uniform distribution. The calculated characteristics are ripple maximum value 35.0%, ripple minimum value 31.0%, uniformity 4.0% / 33.3% = ± 6% = 12%.

  FIG. 75 illustrates an eye pupil of 4 mm and an aperture filling rate of 33% (3 layers, 9 tile type). For this example, the pattern needs to have 1 × 3 unit cells with a uniform column offset of 0.5 pixels.

  A grid distribution using a uniform column 1/2 pixel offset gives a more uniform distribution. The calculated characteristics are: ripple maximum value 34.6%, ripple minimum value 32.7%, uniformity 1.9% / 33.3% = ± 2.85% = 5.7%.

A series of reference designs based on the micro tessellation principle has been developed and summarized below.
1. Standard design-Monochrome, 6 layers, 12 tiles (aperture filling rate 50%), 1mm tessellation-Eye pupil 3mm, uniformity 24%
2. Reference design with re-optimized grating positions in different layers-Monochrome, 6 layers, 12 tiles (aperture filling rate 50%), 1mm tessellation-Eye pupil 3mm, uniformity 20%
3. Reference design using 0.5mm tessellation-Monochrome, 6 layers, 12 tiles (aperture fill factor 50%), 0.5mm tessellation-Eye pupil 3mm, about 3% to 2% over viewing angle Uniformity of 4. Eye pupil 3mm (target: C outdoor AR)
-3 layers, 9 tiles (aperture filling rate 33%), 0.5mm tessellation-Uniformity up to 16.5% 5. Eye pupil 4mm (target: C indoor movie)
・ 3 layers, 9 tiles (aperture filling rate 33%), 0.5mm tessellation ・ Uniformity up to 12%

  Achieving a single tile aperture fill factor of 50% results in significantly improved uniformity over the uniform aperture fill factor of 33% (approximately 5 times uniformity improvement over 3 mm of eye pupil). For 50% aperture fill, 0.5 mm tessellation was significantly better performance than 1 mm tessellation, ie 3% vs. 20% for 3 mm eye pupil. An aperture fill factor of 50% for 9 tiles requires “4.5” (ie 5 layers).

  Eye pupil irradiance uniformity with respect to viewing angle is improved by reducing the size of the main tessellation element and increasing the fill factor of the main tessellation element. Note that decreasing the tile type density for a given layer improves irradiance uniformity with respect to viewing angle. This is because the smaller the tile type, the larger the fill factor of any single main tessellation element type aperture. As the size of the main tessellation element decreases, the MTF (resolution) degrades. Note that an irregular pattern results when the size of the main tessellation element decreases and the density of the main tessellation element type increases. This then allows the opportunity to change the MTF homogenization of the main tessellation and the irradiance angle uniformity viewing angle ripple frequency. The use of small (micro tessellation) within the aperture of the main tessellation improves the overall angular bandwidth of the main tessellation element and therefore provides an opportunity to reduce the number of desired main tessellation element types. It is done.

References

The following patent applications are hereby incorporated by reference in their entirety:
US Provisional Patent Application No. 61 / 627,202, also referred to by the applicant's package number SBG106, with the name “WIDE ANGLE COLOR HEAD MOUNTED DISPLAY”, filed October 7, 2011, filed by the inventor.
Filing date July 22, 2008, international application No. US2008 / 001909 with name “LASER ILLUMINATION DEVICE”,
International application No. US2006 / 043938 with the name “METHOD AND APPARATUS FOR PROVIDING A TRANSPARENT DISPLAY”,
International application GB2010 / 001982 with the name “COMPACT EDGE ILLUMINATED EYEGLASS DISPLAY”,
International application date April 26, 2010, international application GB2010 / 000835 with the name “Compact holographic edge illuminated eyeglass display”,
Filing date November 2, 2010, international application GB2010 / 002023 with the name "APPARATUS FOR REDUCING LASER SPECKLE",
Filing date November 4, 2005, US patent application Ser. No. 10 / 555,661, entitled “SWITCHABLE VIEWFINDER DISPLAY”,
Filing date September 28, 2010, US Provisional Patent Application No. 61 / 344,748, entitled “Eye Tracked Holographic Edge Illuminated Eyeglass Display”,
US provisional patent application whose name is "IMPROVEMENTS TO HOLOGRAPHIC POLYMER DISPERSED LIQUID CRYSTAL MATERIALS AND DEVICES" by the present inventor, which is currently not available but is referred to by the applicant's package number SBG104,
Application date: June 16, 2011, US Provisional Patent Application No. 61 / 457,835, entitled “HOLOGRAPHIC BEAM STEERING DEVICE FOR AUTOSTEREOSCOPIC DISPLAYS”,
International application date July 22, 2008, international application number US2008 / 001909 with the name “LASER ILLUMINATION DEVICE”,
Filing date of the inventor on November 2, 2010, international application GB2010 / 002023 with the name “APPARATUS FOR REDUCING LASER SPECKLE”,
US Provisional Patent Application No. 61 / 573,121, also referred to by the applicant's package number SBG105B, dated September 7, 2011, filed by the present inventor and named “METHOD AND APPARATUS FOR SWITCHING HPDLC ARRAY DEVICES” ,
International application date April 26, 2010, name “COMPACT HOLOGRAPHIC EDGE ILLUMINATED EYEGLASS DISPLAY” (and also referred to by the applicant's bag number SBG073PCT) International Application No. GB2010 / 000835,
United States provisional patent application with the name "IMPROVEMENTS TO CONTACT IMAGE SENSORS" by the present inventor, which is currently not available but is referenced by the applicant's package number SBG100,
Filing date September 16, 2011, US Provisional Patent Application No. 61 / 573,156, entitled “Holographic wide angle near eye display” (SBG Lab Reference No. SBG106A),
Filing date September 19, 2011, US Provisional Patent Application No. 61 / 573,175, entitled “Holographic wide angle near eye display” (SBG Lab Reference No. SBG106B),
Filing date September 19, 2011, US Provisional Patent Application No. 61 / 573,176, entitled “Holographic wide angle near eye display” (SBG Lab Reference No. SBG106C),
Filing date September 25, 2011, US Provisional Patent Application No. 61 / 573,196, entitled “Further improvements to holographic wide angle near eye display” (SBG Lab Reference No. SBG106D),
Filing date October 7, 2011, US Provisional Patent Application No. 61 / 627,202, entitled “Wide angle color head mounted display” (SBG Lab Reference No. SBG106),
Application date April 25, 2012, US Provisional Patent Application No. 61 / 687,436, entitled “Improvements to holographic wide angle head mounted display” (SBG Lab Reference No. SBG109)

  Conclusion All materials such as documents cited in this application, including but not limited to patents, patent applications, articles, books, academic papers and web pages, are clearly indicated in their entirety, regardless of the format of such materials. Incorporated by reference. In the event that one or more of the incorporated materials, such as literature, differs from or contradicts this application including, but not limited to, defined terms, term usage, described techniques, etc., this application takes precedence.

  Although the present teachings have been described in conjunction with various embodiments, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications and equivalents, as will be appreciated by those skilled in the art.

  While various embodiments of the invention have been described and illustrated herein, those skilled in the art will recognize that various other functions may be performed to perform the functions described herein and / or obtain results and / or one or more advantages. Means and / or structures are readily foreseen and each such variation and / or modification is considered to be within the scope of the embodiments of the invention described herein. More generally, as those skilled in the art will readily appreciate, all parameters, dimensions, materials and configurations described herein are intended to be exemplary and actual parameters, dimensions, materials and / or configurations may be Depending on the particular application or applications in which the teachings of the present invention are used. Those skilled in the art will appreciate many equivalent examples to the specific embodiments of the invention described herein. Therefore, it should be understood that the above-described embodiments are presented by way of example only and that they are different from those specifically described and claimed within the scope of the appended claims and their equivalents. It is that the embodiment of the present invention can be implemented in an aspect. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more of such features, systems, articles, materials, kits and / or methods may be used in accordance with the present disclosure if such features, systems, articles, materials, kits and / or methods are consistent with each other. Are included within the scope of the present invention.

  Moreover, the technique described here can be embodied as a method in which at least one example is given. The actions performed as part of the method are ordered in any suitable manner. Thus, multiple embodiments can be constructed in which operations are performed in a different order than that illustrated. These include performing several operations simultaneously, even though they are shown as sequential operations in the illustrated embodiment.

  All definitions defined and used herein should be understood to dominate the dictionary definitions, definitions in documents incorporated by reference, and / or the ordinary meaning of the defined terms.

  The indefinite articles "one" and "one" as used herein and in the claims should be understood to mean "at least one" unless explicitly stated otherwise. Any ranges cited herein are inclusive.

  The terms “substantially” and “about” as used throughout this specification are used to describe and explain minor variations. For example, they may refer to ± 5% or less. For example, ± 2% or less, ± 1% or less, ± 0.5% or less, ± 0.2% or less, ± 0.1% or less, or ± 0.05% or less.

  As used herein and in the claims, the phrase “and / or” is used to refer to “one side” of elements that are concatenated, ie, elements that exist in some cases combined and others exist in isolation. It should be understood to mean “or both”. Multiple elements listed by “and / or” should be construed in the same manner, ie, “one or more” of the connected elements. Other elements than those specifically identified by the “and / or” clause may also be presented as options, regardless of whether they are associated with the specifically identified elements. Thus, as a non-limiting example, a reference to “A and / or B” when used with an open-ended word such as “includes” only in one embodiment (optionally other elements than B) In other embodiments, only B (optionally including elements other than A) may be mentioned, and in another embodiment, both A and B (optionally including other elements) may be mentioned.

  As used herein and in the claims, “or” should be understood to have the same meaning as “and / or” described above. For example, “or” or “and / or” when separating items in an enumeration is inclusive, ie includes a predetermined number or elements of the enumeration and at least one of the additional items not listed as options. Should be construed as including one excess. When used as “only one” or “exactly one” or “consisting of” in a claim, only the terms explicitly stated otherwise are in the prescribed number or list of elements Note that it contains exactly one element. In general, the term “or” as used herein is exclusive when preceded by an exclusive term such as “any”, “one”, “only one”, or “exactly one”. Should only be construed as indicating alternatives (ie, “one or the other but not both”). “Consisting essentially of” as used in the claims has the ordinary meaning used in the field of patent law.

  As used herein and in the claims, the phrase “at least one” associated with an enumeration of one or more elements is at least one selected from any one or more of the elements in that element enumeration. Means one element, but does not necessarily include at least one of each element specifically recited in the element list, and does not exclude any combination of elements in the element list. It should be understood that there is nothing. This definition also includes whether a plurality of elements other than the elements specifically identified in the list of elements referred to by the phrase “at least one” relate to the elements specifically identified. It also allows it to be present as an option. Thus, as a non-limiting example, “at least one of A and B” (or equivalently “at least one of A or B” or equivalently “at least one of A and / or B”) In one embodiment, B remains absent (and optionally includes elements other than B), optionally A includes one excess, and in another embodiment A remains absent (and optional). At least one B, optionally including one excess), and in yet another embodiment, at least one, optionally including A, and at least one, optionally exceeding one Including B (and optionally including other elements).

  In the claims, as in the description above, traditional phrases such as “include”, “have”, “include”, “accompany”, “hold”, “consist of”, etc. Should all be understood as meaning open end, ie including but not limited to. Only the traditional phrases “consisting of” and “consisting essentially of” are respectively closed or semi-closed traditional phrases as defined in US Patent Office Patent Examination Guidelines Section 2111.03.

  The claims should not be read as limited to the described order or elements unless stated to that effect. It should be understood that various changes in form and detail may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims. All embodiments within the spirit and scope of the following claims and their equivalents are claimed.

Claims (16)

An apparatus for displaying an image,
An input image node configured to provide at least a first image modulated light and a second image modulated light;
A holographic waveguide device configured to propagate at least one of the first image modulated light and the second image modulated light in at least a first direction;
The holographic waveguide device includes a plurality of multiple grating elements,
The plurality of multiple grating elements includes a first multiple grating element and a second multiple grating element disposed in at least one layer;
The first multiple grating elements and the second multiple grating elements are interspersed in the at least one layer;
The first multiple grating element and the second multiple grating element have a first prescription and a second prescription, respectively;
The first image modulated light and the second image modulated light are respectively modulated by a first viewing angle (FOV) and second FOV image information,
The first multiple grating element is configured to deflect the first image modulated light into a first multiple output light beam that forms a first FOV tile;
The second multiple grating element is configured to deflect the second image modulated light into a second multiple output beam that forms a second FOV tile;
In the at least one layer, the plurality of multiple grating elements have an integer number N1 different prescriptions interspersed in the first band;
Wherein the first band, N1> N2 integer number N2 of different formulations of elements is, N2> N3 integer N3 or different formulations of elements that are, and N3> N4 integer N4 or different formulations of elements is A device that abuts the band including the left and right continuously. The apparatus of claim 1, wherein the first multiple grating element and the second multiple grating element are tessellated into a predetermined pattern. The first multiple grating element and the second multiple grating element are tessellated into one predetermined pattern, and the predetermined pattern is at least one of a periodic pattern, an aperiodic pattern, a self-similar pattern, and a random distribution pattern. The device of claim 1, wherein The apparatus of claim 1, wherein all elements in the first multiple grating element or the second multiple grating element are configured to be switched to a diffractive state simultaneously. The apparatus of claim 1, wherein at least one of the first multiple grating element and the second multiple grating element has a shape including at least one of a square, a triangle, and a diamond. The apparatus of claim 1, wherein a plurality of elements of the first multiple grating element have a first geometry and a plurality of elements of the second multiple grating element have a second geometry. . The apparatus of claim 1, wherein at least one of the first multiple grating element and the second multiple grating element has at least two different geometries. The apparatus of claim 1, wherein all multiple grating elements in the at least one layer are optimized for one wavelength. The apparatus of claim 1, wherein at least one of the first multiple grating element and the second multiple grating element in the at least one layer is optimized for at least two wavelengths. The apparatus of claim 1, wherein at least one of the first multiple grating element and the second multiple grating element has a multiplexed prescription optimized for at least two different wavelengths. 2. A device comprising the apparatus of claim 1 wherein the first image modulated light and the second image modulated light are part of a stereoscopic display that provides left and right eye viewpoint views. A device including the apparatus according to claim 1, wherein the device is a part of at least one of an HMD, a HUD, and an HDD. The apparatus of claim 1, wherein image modulated light from at least one grating element of a given prescription is in an exit pupil region bounded by a pupil aperture of a human eye. The apparatus of claim 1, wherein at least one of the first multiple grating element and the second multiple grating element is electrically switchable. A method of displaying an image,
(I) and one input image nodes, the method comprising providing an apparatus which includes a one holographic waveguide device comprising a plurality of multi-grating elements of M and N is an integer (M × N), low said plurality of multiple grating elements interspersed in a single layer without the said at within at least one layer has an integer number N1 of different formulations in a first band, said first band, N1> N2 integer number N2 of different formulations of elements is, N2> N3 is an integer N3 or different formulation components, and N3> N4 band including elements integer N4 or different formulations is is continuously Abutting left and right,
(Ii) generating image modulated light (I, J) by the input image node corresponding to a viewing angle (FOV) tile (I, J) for integers 1 ≦ I ≦ N and 1 ≦ J ≦ M;
(Iii) switching multiple grating elements of the FOV tile (I, J) to these diffraction states;
(Iv) illuminating a plurality of multiple grating elements of the FOV tile (I, J) with image modulated light (I, J);
(V) diffracting the image modulated light (I, J) into an FOV tile (I, J). 16. The method of claim 15, further comprising repeating (ii)-(v) until a complete FOV tile is achieved.

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